Finding History

Spanish explorer Melchor Díaz was one of the first Europeans to visit the area around Imperial Valley in 1540. The explorer Juan Bautista de Anza also explored the area in 1776. After the Mexican-American War, the northern half of the valley was annexed by the U.S., while the southern half remained under Mexican rule. Small scale settlement in natural aquifer areas occurred in the early 19th century, but most permanent settlement was after 1900.

In 1905, torrential rainfall in the American Southwest caused the Colorado River to flood, including canals that had been built to irrigate the Imperial Valley. Since the valley is partially below sea level, the waters never fully receded, but collected in the Salton Sink in what is now called the Salton Sea, the world’s only artificial inland sea.

Imperial County was formed in 1907 from the eastern portion of San Diego County. The county took its name from Imperial Valley, itself named for the Imperial Land Company, a subsidiary of the California Development Company, which at the turn of the 20th century had claimed the southern portion of the Colorado Desert for agriculture. By 1910, the land company had managed to settle and develop thousands of farms on both sides of the border. The Mexican Revolution soon after severely disrupted the company’s plans. 

The county experienced a period of migration of “Okies” from drought-trodden dust bowl farms by the need of migrant labor, and prosperous job-seekers alike from across the U.S. arrived in the 1930s and 1940s, especially in World War II and after the completion of the All American Canal from its source, the Colorado River, from 1948 to 1951. 

#182: Tumco Mines
#193: Picacho Mines
#194: Mountain Springs Station
#350: Mission La Purisima Concepcion (Site of)
#568: Hernando de Alarcon Expedition
#806: Fort Yuma
#808: Camp Salvation
#845: Plank Road

#921: Site of Mission San Pedro y San Pablo de Bicuner
#939: Twentieth Century Folk Art Environments -Charley’s World of Lost Art
#939: Twentieth Century Folk Art Environments -Desert Tower
#944: Site of Fort Romualdo Pacheco
#985: Desert Training Center, California-Arizona Maneuver Area -Camp Pilot Knob
#1008: Yuha Well
#1034: Tecolote Rancho Site