Johnstonville (formerly, Toadtown) is a census-designated place[3] in Lassen County, California.

[4] According to the United States Census Bureau, the CDP has a total area of 8.4 square miles (21.7 km2), of which over 99% is land.

This region experiences warm (but not hot) and dry summers, with no average monthly temperatures above 71.6 °F (22.0 °C).

67 households (18.1%) were made up of individuals, and 26 (7.0%) had someone living alone who was 65 years of age or older.

There were 395 housing units at an average density of 47.0 per square mile (18.1/km2), of which 286 (77.3%) were owner-occupied, and 84 (22.7%) were occupied by renters.

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