Imperial Beach is a beach city in San Diego County, California, United States, with a population of 26,137 as of the 2020 census. It is in the South Bay area of San Diego County, south of downtown San Diego and northwest of downtown Tijuana, Mexico. Imperial Beach is the southernmost city in California and the West Coast of the United States.
History
thumb|left|upright|[[Rancho Melijo, which encompassed all of modern-day Imperial Beach, was granted to Californio ranchero Santiago E. Argüello in 1833.]]
Imperial Beach sits on the traditional territory of the Kumeyaay people, who had established the village of Alyshuwii. Founded in June 1887, the city takes its name from Imperial County, California, a desert climate east. Farmers and land owners from the Imperial Valley came to the area in the late 1880s seeking cooler weather during summer months. In March 1887, over 2,000 laborers descended upon nearby Coronado, California to construct the Hotel del Coronado, the largest resort in the world at the time. A large number of the workers stayed in Imperial Beach and some would later make it their permanent homestead. The city would incorporate in 1956, operating its own mayor–council government providing city fire department service and policing by the formation of its own police department but eventually, years later, through the contracting of services through the San Diego County Sheriff's Department.
Imperial Beach has undergone a makeover to become more visitor-friendly and commercially viable. In 2004, the city began implementing a community redevelopment plan to improve the commercial corridor along Palm Avenue and Seacoast Drive. Aside from a few smaller hotels, Imperial Beach remains a highly residential city with little hotel or motel accommodation for visitors. On September 13, 2010, after many years of planning, demolition officially began on the old Seacoast Inn located off Seacoast Drive. Construction of a $22 million hotel called Pier South Resort was completed in the former Seacoast Inn's place in December 2013.
Geography
Imperial Beach is the most southwesterly located city in the continental United States. According to the United States Census Bureau, the city has a total area of . of it is land and of it (2.67%) is water.
|source 2 = National Weather Service
Environment
Imperial Beach marks the terminus of the Tijuana River watershed and is subject to changes that occur upriver. There have been numerous instances of beach closures and pollutant aerosolization within Imperial Beach as caused by untreated sewage or spills. Beaches have been closed since December 8, 2021.
According to Sumya Karamangla, writing in The New York Times (May 26, 2025): "Every day, 50 million gallons of untreated sewage, industrial chemicals and trash flow from Tijuana, Mexico, into southern San Diego County." The problem "has significantly worsened in recent years as the population of Tijuana has exploded and sewage treatment plants in both countries have fallen into disrepair."