Calpine is a census-designated place in Sierra County, California, United States.

According to the United States Census Bureau, the CDP covers an area of 0.7 square miles (1.8 km2), 99.69% of it land and 0.31% of it water.

From 1921 until 1940, a branch of the Western Pacific Railroad served the town and the mill, working out of Portola, California.

There were 158 housing units at an average density of 221.9 per square mile (85.7/km2), of which 74 (77.1%) were owner-occupied, and 22 (22.9%) were occupied by renters.

[22] Federally, Calpine is in California's 1st congressional district, represented by Republican Doug LaMalfa.