Warner Valley is a census-designated place in Plumas County, California.

Warner Valley sits at an elevation of 5,341 feet (1,628 m).

The 2010 United States census reported Warner Valley's population was 2.

According to the United States Census Bureau, the CDP covers an area of 17.5 square miles (45.4 km2), 99.83% of it land and 0.17% of it water.

The 2010 United States Census reported that Warner Valley had a population of 2.