Andrus Island is an island

Island

An island or isle is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, cays or keys. An island in a river or lake may be called an eyot , or holm...

 in the Sacramento-San Joaquin River Delta in Sacramento County, California

Sacramento County, California

Sacramento County is a county in the U.S. state of California. Its county seat is Sacramento, which is also the state capital. As of 2010 the county had a population of 1,418,788....

, twenty kilometres northeast of Antioch

Antioch, California

Antioch is a city in Contra Costa County, California. Located in the East Bay region of the San Francisco Bay Area along the San Joaquin-Sacramento River Delta, it is a suburb of San Francisco and Oakland. The city's population was 102,372 at the U.S...

. The 3000 hectares (7,413.2 acre) island is bounded on the north, and northwest by the Sacramento River

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...

, on the west, Georgiana Slough, on the southeast, Mokelumne River

Mokelumne River

The Mokelumne River is a river in Northern California. The Upper Mokelumne River originates in the Sierra Nevada mountain range and flows into Pardee Reservoir and then Camanche Reservoir in the Sierra foothills. The Lower Mokelumne River refers to the portion of the river below Camanche Dam...

, 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...

, on the southwest Jackson Slough, and Seven Mile Slough. The island is entirely within the bounds of the immense Rio Vista Gas Field

Rio Vista Gas Field

The Rio Vista Gas Field is a large natural gas field in the Sacramento – San Joaquin River Delta in northern California. Discovered in 1936, and in continuous operation since, it has produced over of gas in its lifetime, and retains an estimated reserve of approximately . p. 62. In 2008 alone,...

, although well drilling pads and associated infrastructure make up only a small part of its land use, which is mainly agriculture.

The city of Isleton

Isleton, California

Isleton is a city in Sacramento County, California, United States. The population was 804 at the 2010 census, down from 828 at the 2000 census. It is located on Andrus Island amid the slough wetlands of the Sacramento-San Joaquin River Delta, on the eastern edge of the Rio Vista Gas Field.The city...

is on Andrus Island.