Patented as a townsite in 1872, the early town of El Dorado derived its name from a sawmill located here. Mountain Ranch, the post office established in 1856, was moved to El Dorado which then became known as Mountain Ranch. A bell, which is now on the historic maker, was used in the local school from 1885 to 1953. Established as Cave City School District in 1855, this school joined with the Banner District in 1946 to become the El Dorado Union Elementary School District.
The town is still inhabited, and as of the 2010 Census, the population was 1,628 and is near the California Cavern State Historic Landmark.
The historic marker is located at the northwest corner of Mountain Ranch Road and Whiskey Slide Road in Mountain Ranch, 17.6 miles northeast of Arnold.
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.