Pioneer is a census-designated place in Amador County, California. It is located 5 miles east-northeast of Pine Grove, at an elevation of 2986 feet, along State Route 88. The community is in ZIP code 95666 and area code 209. The population was 1,094 at the 2010 census.Pioneer Station, built approximately 1925, is located in Pioneer however, it was never a Pony Express stop, a popular fallacy. It was a general store selling gas and water and offering camping sites. The old Pioneer Station still stands and is currently a private residence.A post office opened in Pioneer in 1947.