Jackson is the county seat of Amador County, California. The population was 4,651 at the 2010 census, up from 3,989 at the 2000 census. The city is accessible by both State Route 49 and State Route 88.Geography and geologyAccording to the United States Census Bureau, the city has a total area of 3.7sqmi, all of it land. Jackson Creek traverses the city. Alluvial soils such as Pardee Cobbly Loam is found throughout the Jackson area.