Amador County is located in the Sierra Nevada Mountains of California. As of 2010, the population was 38,091. The county seat is Jackson.

Amador County bills itself as “The Heart of the Mother Lode” and lies within the Gold Country. There is a substantial wine-growing industry in the county.

Amador County is located approximately 45 miles (72 km) southeast of Sacramento in a part of California known as the foothills of the Sierra Nevada Mountains.

According to the U.S. Census Bureau, the county has a total area of 605 square miles (1,566 km²), of which, 593 square miles (1,536 km²) of it is land and 12 square miles (30 km²) of it (1.94%) is water. Water bodies in the county include Lake Amador, Lake Camanche, Pardee Reservoir, Bear River Reservoir, Silver Lake, Sutter Creek, Cosumnes River, Mokelumne River, and Jackson Creek.

Amador County ranges in elevation from approximately 250 feet (76 m) in the western portion of the county to over 9,000 feet (2,700 m) in the eastern portion of the county. The county is bordered on the north by the Cosumnes River and on the south by the Mokelumne River.