Place  /  Explainer

San Diego’s South Bay Annexation Of 1957

Water insecurity, territorial expansion, and the making of a US-Mexico border city.

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]