The Stockton Arch is a geologic feature underlying the Central Valley in California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

 in the vicinity of the delta of the Sacramento

Sacramento River

The Sacramento River is an important watercourse of Northern and Central California in the United States. The largest river in California, it rises on the eastern slopes of the Klamath Mountains, and after a journey south of over , empties into Suisun Bay, an arm of the San Francisco Bay, and...

 and San Joaquin River

San Joaquin River

The San Joaquin River is the largest river of Central California in the United States. At over long, the river starts in the high Sierra Nevada, and flows through a rich agricultural region known as the San Joaquin Valley before reaching Suisun Bay, San Francisco Bay, and the Pacific Ocean...

s, near the city of Stockton

Stockton, California

Stockton, California, the seat of San Joaquin County, is the fourth-largest city in the Central Valley of the U.S. state of California. With a population of 291,707 at the 2010 census, Stockton ranks as this state's 13th largest city...

. The Stockton Arch is an upwarping of the crust beneath the thick sediments of the Central Valley, and is regarded as the subsurface separation between the Sacramento River basin and the San Joaquin River basin.