Butterfield Overland Mail in California

The Butterfield Overland Mail in California was created by the United States Congress on March 3, 1857, and operated until June 30, 1861. Subsequently other stage lines operated along the route until the Southern Pacific Railroad arrived in Yuma, Arizona in 1877.

The route lasted from 1857 to 1861 and became one of the most important roads in the early settlement and development of California.

The Second Division's route from Fort Yuma to Warners Pass followed the Sonora Road, an old Spanish and Mexican trail from Sonora, México to San Diego. The Sonora Road linked with the Kearney Trail that was used during the Mexican–American War by the U.S. Army. During the California Gold Rush the route pioneered by Kearny and Cooke, with the addition of a road from Warner's Pass to the Pueblo of Los Angeles, became the Southern Emigrant Trail used by American immigrants.

The route crossed the Colorado River from New Mexico Territory at present day Yuma, Arizona to Fort Yuma in California, then descended into Baja California Mexico for 129 miles (208 km) to avoid the Algodones Dunes sand barrier in the dry southern Colorado Desert. The Mexican route also provided stations with water in the Sonoran Desert, from the Colorado River's spring flooding into the Alamo River and New River.

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