Jackson was named after Colonel Alden Jackson, and was founded in 1848 around a year-round spring. Settlement of the region by American pioneers was stimulated by the discovery of gold in the Sierra foothills around 1848.
The settlement was named for a local lawyer who was liked by miners named Alden Appola Moore Jackson. Although Amador County was an important mining center, its County seat of Jackson was not typical of the early gold camps. The camp grew quickly, as besides being a popular mining spot, it was also a convenient stopping place on the road from Sacramento to the Southern Mines.
The camp became an important supply and transportation center for the neighboring towns, and by 1850 the population had reached an estimated 1,500. Jackson grew first as a watering hole for cattle, then as one of the earliest and most durable of the Mother Lode's hard rock mining areas. In 1853, Jackson became the county seat of newly formed Amador County, California. Previously, from 1851–1852, it had been the county seat of Calaveras County.