Coarsegold has previously had several names, including Coarse Gold, Gold Gulch, Michaels, Oro Grosso, Texas Flat,and Coarse Gold Gulch. The place was first called Texas Flat after miners from Texas discovered gold there in 1849. By 1874, the name had changed to Michaels, honoring Charles Michaels, a local merchant. A rival mining camp inhabited by Mexicans there was called Oro Grosso, the Spanish translation of coarse gold.
The current name derives from the California Gold Rush of the mid-19th century, when prospectors discovered coarse nuggets of gold in a nearby creek. At one time, several dozen gold mines operated in the area.
The Coarse Gold Gulch post office opened in 1878, changed the name to Goldgulch in 1895 and to Coarsegold in 1899.