Cool, formerly known as Cave Valley, is a small unincorporated community in El Dorado County, California, about 40 miles from Sacramento, the state capital. Cool is at an elevation of 1,532 feet. The population is 4,100 according to the 2010 census and is contained within the area code 530 with a ZIP code of 95614.
It is built on State Route 49 between Auburn and Placerville on a hill at an elevation more than 1,500 feet in an area full of trees, trails, camping, and other recreational activities. The temperature ranges from 75° to 105° Fahrenheit in the summer and 25° to 50° Fahrenheit in the winter.
The first post office was established in 1885. Penobscot Public House, established in 1850, was a way station and stage coach stop during the days of the Gold Rush. The famous Penobscot Ranch still exists today. Today the historic site, including the house built during the days of the Gold Rush and the barn built in 1923, can be viewed by driving down Highway 193 four miles outside of the business center of Cool. Cool offers residents and visitors alike the opportunity to enjoy a peaceful rural residential environment, including small restaurants, as well as the Auburn State Recreational Area, which is open to the public for hiking and horseback riding.