Pine Grove is a census-designated place in Amador County, California. It lies at an elevation of 2513 feet. The population was 2,219 at the 2010 census. It is located at 38°24′47″N 120°39′32″W, along State Route 88. The community is in ZIP code 95665 and area code 209. The current boundaries of Pine Grove include the former mining towns of Clinton and Irishtown. The town also is home to Indian Grinding Rock State Historic Park. A post office opened in Pine Grove in 1856.