The Caldor Fire was a large wildfire that burned 221,835 acres in the Eldorado National Forest and other areas of the Sierra Nevada in El Dorado, Amador, and Alpine County, California, in the United States during the 2021 California wildfire season. The fire was first reported on Saturday, August 14, 2021, and was fully contained on Thursday, October 21, 2021. The Caldor Fire destroyed 1,005 structures and damaged 81 more, primarily in the US Highway 50 corridor and in the community of Grizzly Flats, 2/3 of which was destroyed by the fire.

El Dorado County, officially the County of El Dorado, is a county located in the U.S. state of California. As of the 2020 census, the population was 191,185. The county seat is Placerville. The county is part of the Sacramento-Roseville-Arden-Arcade, CA Metropolitan Statistical Area. It is located entirely in the Sierra Nevada, from the historic Gold Country in the western foothills to the High Sierra in the east. El Dorado County's population has grown as Greater Sacramento has expanded into the region. Where the county line crosses US 50 at Clarksville, the distance to Sacramento is 15 miles. In the county's high altitude eastern end at Lake Tahoe, environmental awareness and environmental protection initiatives have grown along with the population since the 1960 Winter Olympics, hosted at the former Squaw Valley Ski Resort in neighboring Placer County.