Adin (formerly, Adinville and Aidenville) is a census-designated place[3] in Modoc County, California.

Adin, the first town in Modoc County west of the Warner Mountains, was founded in 1869 by Adin McDowell as the supply point for the mining town of Hayden in northern Lassen County, and was named for him in 1870.

[6][7] The Aidenville post office opened in 1871, and changed its name to Adin in 1876.

[4] A 1913 book described Adin as having a population of 200, and as the chief town of the Big Valley.

[10] According to the United States Census Bureau, the CDP covers an area of 3.4 square miles (8.9 km2), 99.82% of it land, 0.18% of it water.

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

45 households (36.3%) were made up of individuals, and 19 (15.3%) had someone living alone who was 65 years of age or older.

There were 144 housing units at an average density of 41.8 per square mile (16.1/km2), of which 77 (62.1%) were owner-occupied, and 47 (37.9%) were occupied by renters.

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