Gwin Mine, Paloma, and Lower Rich Gulch were mined for placer gold in 1849, and quartz was discovered by J. Alexander in 1851. The town was after the nearby Paloma Mine, which was renamed the Gwin Mine after William McKendree Gwin, California's first Senator, purchased the mine in 1867. After yielding millions of dollars of gold, the Gwin Mine closed in 1908.
In the late 1890s, landowner Benjamin Franklin Foster subdivided an area south of the mine for a townsite. The town needed its own post office, however Paloma was already the name of a post office elsewhere in California, so the town was instead given the name Fostiera. A decade after the Gwin Mine closed in 1908, the post office closed. Today, a few buildings remain from the Gold Rush era.
Along with Mark Twain’s famous "The Celebrated Jumping Frog of Calaveras County" story that spun into an annual fair and Jumping Frog Jubilee, Calaveras County is rich with Gold Rush history and folklore. Remnants of the railroads and Hispanic culture add to the charm of the county located in the Sierra Nevada foothills. Calaveras Big Trees State Park, a preserve of Giant Sequoia trees, and the uncommon gold telluride mineral Calaverite was discovered in the county in 1861, and is named for it.
Calaveras is a Spanish word meaning "skull." The name was first given to the river because of the great quantities of human skulls found along the lower reaches of the river.
Calaveras County is famous for its lode and placer mines, and the largest gold nugget from the United States was taken from the Morgan Mine at Carson Hill in 1854, weighing 214 pounds. For many years it was the principal copper-producing county in California. Cement deposits from its vast limestone deposits has become one of the county's major industries in recent years.