Editor’s note: In anticipation of the Society for American City and Regional Planning History’s (SACRPH) 2024 conference to be held in San Diego on the campus of the University of California San Diego, The Metropole’s theme for February is San Diego. This is the third of four entries for the month. For more information about SACRPH 2024, see here. For previous entries in the series click here.

By Kevan Q. Malone

In July 1953 the president of the San Ysidro Chamber of Commerce, James R. Johnson, wrote to Congressman Bob Wilson regarding a recent proposal to expand the capacity of customs and immigration inspection at the San Ysidro Port of Entry. This US border-crossing station connected the Mexican city of Tijuana to the American town of San Ysidro in the unincorporated South Bay area of San Diego County. A column of promotional text on the chamber’s official stationery, on which Johnson wrote, highlighted some of the American border community’s positive attributes. Characterizing the town as a “small, smart city located 15 miles south of San Diego at the southern terminus of US Highway 101,” the chamber boasted that the region’s climate was the “most equable and pleasant in Southern California.” It celebrated the town’s “ultra-modern” public school, as well as its civic center and library, and noted that various public service clubs enhanced “the social life of the community.” Above the column was the organization’s longtime marketing banner: “San Ysidro: ‘The Gateway to Old Mexico.’”^[1]

The San Ysidro chamber was largely in the role of luring new businesses and taxpaying residents to its community, so it is no wonder that embellishment was its method of operation. But a few inaccuracies in the promotional text had less to do with exaggeration than timing, and changing circumstances on the international border had recently rendered the stationery outdated. One bullet point stated that the San Ysidro border station was the “second busiest port of entry” in the United States.^[2] In fact, during the fiscal year ending on June 30, 1953, the San Ysidro port became North America’s busiest international border crossing.^[3] A second inaccuracy noted that the area had “adequate fire protection.”^[4] Actually, firefighting was one of several municipal services that became inadequate as postwar San Ysidro gained more residents. Perhaps most egregious among the stationery’s inaccuracies was the statement that the San Ysidro Irrigation District furnished “abundant water at very low rates.”^[5] In fact, on the same day that Johnson wrote to Wilson, the director of the irrigation district wrote a letter thanking California governor Earl Warren for recently appointing a local committee of officials to help the International Boundary and Water Commission (IBWC) find a solution to the problem of water scarcity in the districts of the unincorporated South Bay—San Ysidro, Nestor, Palm City, Imperial Beach, and adjacent farming areas—that relied on the aquifers below their feet in the binational Tijuana River basin.^[6]

In 1953 a group of South Bay residents searching for solutions to these problems—especially the water problem—filed a petition for their unincorporated districts to be annexed by the city of San Diego. Four years passed before this measure was completed. Under California law, San Diego first had to establish contiguity with the area proposed for annexation. To achieve this, the city annexed an arbitrary, narrow strip of the underwater ground below the San Diego Bay in August 1954, connecting downtown San Diego to the bay’s southern shore, near Imperial Beach—a legally questionable action that was challenged by neighboring cities.[7] South Bay annexation proponents then had to convince a majority of voters within the proposed area to support the measure in order to become part of San Diego. After a failed attempt in 1956, residents of a 21.5-square-mile area adjacent to the international border finally voted on July 16, 1957, to do just that. [8] The annexation took effect two months later on September 13. It did not include Imperial Beach, which incorporated as its own city after the previous year’s failed vote.[9]

The South Bay annexation extended the authority of the San Diego Police Department southward to the international border zone—an area of increasing public concern, as a growing number of American juveniles appeared to be scoring drugs in Tijuana and returning home through San Ysidro. Additionally, by placing the San Ysidro Port of Entry within San Diego’s municipal limits, the annexation increased the city’s economic power. While other American cities along the border—from Calexico, California, to Brownsville, Texas—developed largely as international gateway towns, channeling trade between the United States and Mexico, San Diego had taken root primarily in relation its seaport. Following the annexation, however, the border station at San Ysidro assumed an increasingly significant role in San Diego’s economy.

The tradeoff for San Diego in acquiring this territory was water, one of the scarcest but most essential resources for urban growth and sustainability in the semiarid climate of Southern California. With the South Bay annexation, San Diego used the promise of water security to expand its political and economic power southward to the US-Mexico border.

It was the international border that created the problem of water insecurity in the first place. By dividing the Tijuana River basin between the United States and Mexico, the border complicated water management. In the “Sunbelt borderland” of the South Bay, the postwar economic boom and rapid urban growth on both sides of the international divide threatened the survival of communities. San Diego seized the opportunity for territorial expansion. In short, the border created the very conditions that took San Diego from its seaport origins to an international border city.

Bayfront Development, Border Area Policing, and the Port of Entry

The annexation proposal by South Bay residents in 1953 was good news for the city of San Diego, which had numerous incentives to take possession of the area. First, the San Diego Chamber of Commerce and its allies in the city government believed that eliminating county territory adjacent to the San Diego Bay and concentrating all bayfront lands in only four incorporated cities—San Diego and the suburbs of National City, Chula Vista, and Coronado—would facilitate  economic development around the harbor.^[10]As the San Diego chamber’s president noted in 1955, the annexation would “stabilize” the proposed area, “provide for its planned growth,” and “assist in the formation of a unified plan for Harbor and Industrial Development.”[11]

Second, authorities in San Diego believed that the proposed annexation would allow the city to police the area near the port of entry—an area previously patrolled by the San Diego County Sherriff’s Office.[12] The increase in cross-border traffic in recent years paralleled a rise in drug trafficking. In a letter to Congressman Wilson, the San Diego customs director expressed his belief that expanding the border crossing facilities to allow for more thorough inspection of vehicles would also serve the purpose of “preventing the smuggling of narcotics.”^[13] San Diego police would not monitor the San Ysidro Port of Entry, which would remain the responsibility of federal agencies. But authority to police the streets just north of the border could increase the city’s control over an area of great concern for law enforcement around the county.

Policing in the border zone also involved efforts to restrict unaccompanied American juveniles from entering Mexico. This practice had roots in the Prohibition Era, when Protestant moral crusaders in Southern California persuaded local authorities to post a “Juvenile Protective Officer” to prevent minors from going to Tijuana.^[14] Officials in postwar San Diego reignited this effort. Although the agency had no authority to stop them, the San Diego County Sheriff’s office began counting juveniles entering Tijuana in 1952.^[15] If the San Ysidro Port of Entry were to come within the limits of San Diego, the city would have authority to police these juveniles as well.

Third, San Diego business interests believed that the city’s economy would benefit more directly from cross-border trade if the port of entry were within city limits.^[16] As the populations of Tijuana and neighboring Mexican cities grew after 1945, markets for American exports increased. In 1952, $64.5 million worth of exports passed through the San Diego Customs District, mostly overland into the Mexican state of Baja California through the border crossings at San Ysidro and Tecate in San Diego County and at Calexico and Andrade in Imperial County. These numbers increased to almost $68 million in 1953 and nearly $80 million in 1954.^[17] Automobiles, trucks, buses, and automotive parts ranked first among the major US exports to Baja California in 1952, with petroleum products, including gasoline and other motor fuels, ranking second.^[18]

The exportation of building materials to Baja California in 1952—including lumber, cement, steel reinforcing bars for concrete, asphalt roofing, gypsum plaster board, floor and wall tiles, and machinery used in construction, as well as paints, stains, and enamels—indicated large-scale construction south of the border.^[19] Baja California also imported many food products through the San Diego Customs District, especially lard, eggs, wheat, evaporated milk, beans, potatoes, poultry, and fruit juices. In fact, in the early 1950s, larger shipments of many foods crossed the border through the customs district of San Diego than passed through the Los Angeles district to overseas markets.^[20]

Meanwhile, imports through the San Diego district—more than half of which originated in Mexico—had a total value of over $41 million in 1952, over $17 million in 1953, and over $19 million in 1954.^[21] During the fall of 1952 and winter of 1953, about 375 trucks a day were crossing the border at Tijuana in each direction, making adequate inspections by US customs enforcers nearly impossible. The director of customs at San Ysidro highlighted this problem in a letter to Congressman Wilson in 1953, noting that inspectors had been “greatly handicapped by lack of parking space for the accommodation of trucks particularly, and other vehicles undergoing customs treatment.”^[22]

Perhaps the most common form of trade between California and Baja California was the exchange of money between consumers and businesses on opposite sides of the border. During fiscal year 1945—from July 1, 1944, to June 30, 1945—2.8 million passengers in over 754,000 vehicles crossed the border at San Ysidro. Five years later, in fiscal 1950, almost 5.5 million passengers in 1.6 million vehicles passed through this gate.^[23] In fiscal 1953, when the San Ysidro port became the busiest international border crossing, there were 11.7 million passengers in 3.1 million vehicles. This was roughly a half a million more cars than those that crossed from Windsor, Ontario, to Detroit, Michigan—previously the United States’ busiest international land port.^[24] Pedestrian crossings at San Ysidro fell from 1.3 million in fiscal 1945 to 1.1 million in fiscal 1950^[25]—most likely because of San Diego’s declining military population after World War II—but increased rapidly with the expansion of the region’s Cold War military-industrial economy in the early 1950s, reaching 1.3 million in fiscal 1953.^[26]

Table 1: Persons and Automobiles Entering the United States at the San Ysidro Port of Entry, Fiscal Year 1950-1953

Fiscal Year (July 1- June 30)	Automobiles	Passengers	Pedestrians	Total Number of Persons
1949-1950	1,640,804	5,458,235	1,120,264	6,578,499
1950-1951	2,117,557	5,998,400	1,298,737	7,279,137
1951-1952	2,907,668	7,611,469	1,227,323	8,838,792
1952-1953	3,123,862	11,698,824	1,337,177	13,036,001

These border crossers were largely consumers. Between 1951 and 1954, the amount of money spent by Baja California residents in California increased from $50,450,000 to $113,913,000, and money spent by residents of Tijuana in the San Diego area rose from $30,443,000 to $50,788,000. By comparison, money spent by US citizens in Baja California increased from $81,220,000 to $152,637,000, and money spent by US citizens in Tijuana rose from $55,980,000 to $82,296,000.^[27] Much of the money spent by residents of Mexico in San Diego County was in the town of San Ysidro and other areas close to the border within the unincorporated South Bay.^[28] For these reasons, San Diego policymakers believed that annexing this area would be a boon to the city’s economy.

Table 2: Estimated Amount of Money Spent Across the Border Per Year, 1951-1957

Year	Money Spent by Residents of Baja California in California	Money Spent by residents of the United States in Baja California	Money Spent by Residents of Tijuana in the San Diego Area	Money Spent by Residents of San Diego County in Tijuana
1951	$50,450,000	$81,220,000	$30,443,000	$55,980,000
1952	$51,796,000	$83,068,000	$21,972,000	$46,166,000
1953	$83,174,000	$121,854,000	$44,711,000	$73,101,000
1954	$113,913,000	$152,637,000	$50,788,000	$82,296,000
1955	$102,550,000	$151,206,000	$45,636,000	$83,192,000
1956	$136,808,000	$217,022,000	$62,452,000	$114,557,000
1957	$142,097,000	$245,178,000	$75,251,000	$155,922,000

Water and Municipal Services for the South Bay

If San Diego had much to gain from the proposed annexation, so did the residents of the South Bay—including municipal services such as garbage collection, policing, and fire protection.[29] According to a 1955 study by the San Diego Fire Department, only one paid firefighter and fifteen volunteers manned San Ysidro’s station, while the fire department of Imperial Beach consisted of two paid men, who worked six days a week from Monday through Saturday, and fifty volunteers. Neither town had a fire alarm, all reports had to be telephoned in, and firefighters had no radio equipment. The stations were “substandard” and would “require considerable improvement” if they the city of San Diego were to take them over. Both of these unincorporated communities also contained inadequate hydrants and pumping facilities—infrastructure that “could not be depended upon in event of a large fire.”^[30]

But the central issue for annexationists in the unincorporated South Bay was water. The problem of water insecurity grew out of several historical developments that began with the US conquest of northern Mexico. The 1848 Treaty of Guadalupe Hidalgo ended the Mexican-American War and transferred roughly half of Mexico’s territory to the United States. The western portion of the new border intersected the northbound Tijuana River and arbitrarily divided the river’s basin between two sovereign nation-states.[31] This division set the stage for future problems of water management.

Mexico’s Rodríguez Dam—built on the intermittent Tijuana River in the 1930s to provide water for the budding city of Tijuana—prevented mountain runoff from flowing into the river valley and replenishing the aquifers on which the American communities downstream in the South Bay depended. When drought struck the region in 1944, the basin’s limited water could not sustain the urban growth that Southern California’s wartime and postwar economy was producing on both sides of the border. In 1950 Mexican authorities began installing wells along the Tijuana River to supplement the reservoir’s rapidly diminishing supply.[32] The aquifers below the river basin recognized no political boundary, and the extraction of groundwater south of the border reduced the water on which the American communities north of the border relied. Any one of these developments alone—the dam, the drought, and Tijuana’s population growth—might not have made a significant difference for the South Bay. But taken together, these factors threatened the survival of San Ysidro and neighboring towns.

The best solution came from the Metropolitan Water District of Southern California (MWD), which was formed in 1928 to construct the Colorado River Aqueduct for the Los Angeles metro area. The MWD began supplying water to the San Diego County Water Authority (CWA) in 1947.^[33] Annexation by San Diego would allow the South Bay to access this water. It was with these goals in mind that residents of the South Bay voted to join the city of San Diego in 1957.

The South Bay Annexation and Its Aftermath

Water scarcity in the binational Tijuana River basin set in motion a series of developments that resulted in San Diego’s expansion to the Mexican border. Without the problem of water insecurity in the 1950s, South Bay residents may still have petitioned for annexation by San Diego at some point in the future to receive the municipal services they desired. San Diego would likely have approved such a proposal, given the desires of policymakers for bayfront development, control over the border zone, and the economic benefits of having the port of entry within city limits. Nonetheless, it was the water problem that gave San Diego the opportunity to take possession of the South Bay in the 1950s and establish authority over this area. In this sense, the South Bay annexation might be seen as a climax in the history of water management in the San Diego–Tijuana border region.

Following the annexation, San Diego rolled out municipal services incrementally to the South Bay. Garbage collection began four days after the annexation took effect.^[34] The next day, the San Diego Fire Department took over the firehouse in San Ysidro, which the San Digo Public Works Department had recently remodeled. A four-man crew of firefighters and their captain would serve the entire annexed area.^[35]

Policing also increased in the border area. In July 1958, less than a year after the San Ysidro Port of Entry came within the city’s boundaries, the San Diego Police Department began a 24-hour check to prevent unaccompanied American juveniles from crossing the border. Between that time and February 1960, the police stopped 14,586 minors from entering Tijuana.^[36] In a letter to Congressman Wilson, the chief of the San Diego Police Department concluded that the “beginning volume in 1958” and the “steadily diminishing number of juveniles turned back” indicated the “effectiveness of the program.”^[37]

At the time of the annexation in 1957, the San Diego County Water Authority (CWA) was planning for a second aqueduct to bring more Colorado River water to the city of San Diego and surrounding communities. Dedicated on December 1, 1960, the pipeline ran from the  MWD’s Colorado River Aqueduct to the CWA’s Otay Reservoir in the southern portion of San Diego County, not far from the international border.[38] Colorado River water began flowing to San Ysidro just over a year later in January 1962, following the construction of pipelines from the reservoir.[39]

While the residents of San Ysidro achieved water security, Tijuana’s troubles persisted through the 1960s, as Mexico’s Border Industrialization Program fueled rapid urban growth south of the border. Under a 1944 treaty with the United States, Mexico was entitled to a portion of the water of the Colorado River. Unlike San Diego, however, Tijuana lacked the funding to pay for a pipeline. Thus, on June 13, 1972, the US and Mexican sections of the IBWC approved an agreement for delivery of Colorado River water from San Diego’s Otay Reservoir to the border at Tijuana on an emergency basis for no more than 5 years—during which the Mexican  government would be expected to develop its own permanent waterworks.^[40] Taxpayers in Tijuana would pay for the delivery of the emergency water from San Diego but not for the water itself, to which Mexico was entitled under the treaty. Two months after the agreement, water began flowing from the Parker Dam on the Colorado River between California and Arizona to Tijuana by way of the MWD’s Colorado River Aqueduct, the CWA’s Second San Diego Aqueduct, and a newly constructed pipeline from the Otay Reservoir to the international border, for a total distance of 323 miles.^[41]

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Kevan Q. Malone is a postdoctoral fellow in the Humanities Center at Texas Tech University. He holds an MA in American Studies from the CUNY Graduate Center and a PhD in history from UC San Diego. His book project examines urbanization, environmental transformation, and cross-border city planning in the San Diego–Tijuana area. Kevan’s research has been funded by the American Historical Association, the Society for Historians of American Foreign Relations, the Huntington Library, and the special collections libraries of UC Berkeley, UCLA, and UC San Diego. His writings have also appeared in the Washington Post and the San Diego Union-Tribune.

Featured image (at top): Scene outside the United States Custom House (also known as the Old Customs House) in San Ysidro, San Diego, California, north of the Mexico and United States border at the San Ysidro Port of Entry (2022). Photograph by Carol M. Highsmith, Prints and Photographs Division, Library of Congress.

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[1] James Johnson to Bob Wilson, July 17, 1953, MS-0044, Box 62, Folder 4, Robert Carleton Wilson Papers, San Diego State University Special Collections and University Archives, San Diego, CA (hereafter cited as Wilson Papers).

[2] Ibid.

[3] Howard Morin, “Customs Lists San Ysidro as Busiest Port,” San Diego Union, July 10, 1953.

[4] James Johnson to Bob Wilson, July 17, 1953, MS-0044, Box 62, Folder 4, Wilson Papers.

[5] Ibid.

[6] C.G. Buehrer to Earl Warren, July 17, 1953, C114, Box 61, Folder 3, Goodwin J. Knight Papers, California State Archives, Sacramento, CA.

[7] “Bay Strip Annexed by City Council,” San Diego Union, August 11, 1954.

[8] Abstract of votes cast, by Lex Lord, January 26, 1956, Record Series: Annexation, Box 7844, Folder 9, San Diego City Clerk Archives; “Vote Returns by Precinct,” San Diego Union, January 25, 1956.

[9] “South Bay Annexation Approved by State,” San Diego Union, September 17, 1957; Warren L. Hanna, ed. Opinions of the Attorney General of California, Volume 31 (January – June, 1958) (Pomona, CA: Hanna Legal Publications, 1963), 59.

[10] “San Diego, Chula Vista Seek South Bay Lands,” San Diego Union, December 22, 1953; “Annexation is Called Port Developer,” San Diego Union, December 23, 1953; “Race Develops in S.D. Bay Annexation,” Chula Vista Star, December 24, 1953; Shelly J. Higgins, This Fantastic City, San Diego (San Diego: City of San Diego, 1956), 154-155; Richard Bigger, Metropolitan Coast: San Diego and Orange Counties, California (Los Angeles: Bureau of Governmental Research, 1958), 28; California State Assembly Interim Committee on Municipal and County Government, Transcript of Proceedings: Annexation and Related Incorporation Problems (1960), 61; Roberto D. Hernández, Coloniality of the U-S///Mexico Border: Power, Violence, and the Decolonial Imperative (Tucson: University of Arizona Press, 2018), 84.

[11] Arnold Klaus, History of the San Diego Chamber of Commerce (San Diego: San Diego Chamber of Commerce), 694-695, RCC 381.062/MICROFILM, Marilyn and Gene Marx Special Collections Center, San Diego Public Library, San Diego, CA.

[12] Hernández, Coloniality of the U-S///Mexico Border, 82.

[13] C.W. Pollock to Bob Wilson, March 6, 1953, MS-0044, Box 140, Folder 7, Wilson Papers.

[14] Edna Snook to Herbert Hoover, June 7, 1929, 537, Box 23, Folder 4, Philip David Swing Papers, UCLA Library Special Collections, Los Angeles, CA.

[15] “Tijuana Businessmen Protest Roadblocks,” Los Angeles Times, February 5, 1952.

[16] Hernández, Coloniality of the U-S///Mexico Border, 82.

[17] “Baja California Offers Expanding Market for Southern California Industry,” by U.S. Department of Commerce, June 8, 1953, MS-0040 Box 78, Folder 21, San Diego Chamber of Commerce Records, SDSU Special Collections and University Archives, San Diego State University, San Diego, CA (hereafter cited as San Diego Chamber of Commerce Records; Edwin Bates to Lucille Mortimer, May 18, 1955, MS-0040 Box 78, Folder 21, San Diego Chamber of Commerce Records.

[18] “Baja California Offers Expanding Market for Southern California Industry,” by U.S. Department of Commerce, June 8, 1953, MS-0040 Box 78, Folder 21, San Diego Chamber of Commerce Records.

[19] “Baja California Offers Expanding Market for Southern California Industry,” by U.S. Department of Commerce, June 8, 1953, MS-0040 Box 78, Folder 21, San Diego Chamber of Commerce Records.

[20] Ibid.

[21] Ibid; Edwin Bates to Lucille Mortimer, May 18, 1955, MS-0040 Box 78, Folder 21, San Diego Chamber of Commerce Records.

[22] C.W. Pollock to Bob Wilson, March 6, 1953, Box 140, Folder 7, Wilson Papers.

[23] C.W. Pollock to Bob Wilson, March 6, 1953, MS-0044, Box 140, Folder 7, Wilson Papers.

[24] Howard Morin, “Customs Lists San Ysidro as Busiest Port,” San Diego Union, July 10, 1953.

[25] Ibid.

[26] Ibid.

[27] Flavio Olivieri to Oscar Kaplan, November 26, 1958, MSS 0178, Box 34, Folder 8, Oscar and Rose Kaplan Public Opinion Surveys, UCSD Special Collections and Archives, University of California, San Diego, San Diego, CA.

[28] For more on the history of Tijuana residents shopping in California, see: Magalí Murià Tuñón, “Enforcing Boundaries: Globalization, State Power and the Geography of Cross-border Consumption in Tijuana, Mexico,” (PhD diss., University of California, San Diego, 2010).

[29] “Notice of Intention,” September 1, 1955, Record Series: Annexation, Box 7844, Folder 3, San Diego City Clerk.

[30] “Report on proposed annexation of Imperial Beach, San Ysidro, and adjacent lands to the City of San Diego,” by A.C. Penrose, May 11, 1955, Record Series: Annexation, Box 7844, Folder 11, San Diego City Clerk Archives.

[31] For more on the establishment of the western portion of the U.S.-Mexico border, see Rachel St. John, Line in the Sand: A History of the Western U.S.-Mexico Border (Princeton: Princeton University Press, 2011).

[32] “Water Problems of the Tia Juana Basin” by John M. Page, February 9, 1955, WRCA 071 Box 31, Folder 144H, Charles H. Lee Papers and Photographs, UCR Water Resources Collections & Archives, University of California, Riverside, Riverside, CA.

[33] San Diego County Water Authority, Second Annual Report for Period July 1, 1946 to June 30, 1948 (San Diego: Neyenesch Printers, Inc., 1948), 36.

[34] “Council Acts on Service in South Bay,” San Diego Union, September 20, 1957.

[35] “Firemen Begin San Ysidro Duty,” San Diego Union, September 18, 1957; “City Firemen stationed in San Ysidro,” San Diego Union, September 19, 1957.

[36] A.E. Jansen to Bob Wilson, March 25, 1960, MS-0044, Box 139, Folder 5, Wilson Papers.

[37] Ibid.

[38] San Diego County Water Authority, Fifteenth Annual Report of Authority Operations for Fiscal Year Ending June 30, 1961 (San Diego: 1961), 34; “Dedication of San Diego Aqueduct Held,” Los Angeles Times, December 2, 1960.

[39] Neil Ball, “City Water Flows into San Ysidro,” San Diego Union, January 18, 1962.

[40] Minute No. 240: Emergency Deliveries of Colorado River Water for Use in Tijuana, International Boundary and Water Commission, June 13, 1972: https://www.ibwc.gov/wp-content/uploads/2023/05/Min240.pdf.

[41] International Boundary and Water Commission, Final Environmental Impact Statement: Emergency Water Delivery of Colorado River Water to Tijuana, Baja California, Mexico, Via Facilities in California (El Paso: IBWC, 1972); Ray Hebert, “Badly Needed Water Flows South,” Los Angeles Times, November 5, 1972.