Westhaven-Moonstone is a census-designated place (CDP) located in Humboldt County, California, United States.

According to the United States Census Bureau, the CDP has a total area of 8.1 square miles (21 km2), of which, over 99% of it is land.

170 households (31.0%) were made up of individuals, and 38 (6.9%) had someone living alone who was 65 years of age or older.

There were 498 housing units at an average density of 61.6 per square mile (23.8/km2).

28.5% of all households were made up of individuals, and 5.5% had someone living alone who was 65 years of age or older.

Out of the total population, 16.9% of those under the age of 18 and 0.0% of those 65 and older were living below the poverty line.

In the state legislature, Westhaven-Moonstone is in the 2nd Senate District, represented by Democrat Mike McGuire,[5] and the 2nd Assembly District, represented by Democrat Chris Rogers.

[6] Federally, Westhaven-Moonstone is in California's 2nd congressional district, represented by Democrat Jared Huffman.