Alta Sierra is a census-designated place in Nevada County, California, United States. The population was 6,911 at the 2010 census, up from 6,522 at the 2000 census. Alta Sierra was laid out by property developers in the 1960s. Alta Sierra is a golf course community, with homes built around the Alta Sierra Country Club, a semi-private 18 hole course b…Alta Sierra is a census-designated place in Nevada County, California, United States. The population was 6,911 at the 2010 census, up from 6,522 at the 2000 census. Alta Sierra was laid out by property developers in the 1960s. Alta Sierra is a golf course community, with homes built around the Alta Sierra Country Club, a semi-private 18 hole course built in 1964. The community has a member-owned airport with a 2800-foot runway. The community is located just east of California State Highway 49, at an elevation of approximately 2300 feet, between the cities of Grass Valley, California to the north and Auburn, California to the south. There is a small commercial district with several restaurants, a gas station, a market and personal service businesses. There is also an elementary school and a motel.