Castine (/ˈkæstiːn/ KASS-teen[5]) is a village in Darke County, Ohio, United States.

[6]: 584 According to the United States Census Bureau, the village has a total area of 0.08 square miles (0.21 km2), all land.

31.5% of all households were made up of individuals, and 18.5% had someone living alone who was 65 years of age or older.

The racial makeup of the village was 98.45% White, 0.78% African American, and 0.78% from two or more races.

7.0% of all households were made up of individuals, and 4.7% had someone living alone who was 65 years of age or older.

There were 7.7% of families and 7.0% of the population living below the poverty line, including no under eighteens and none of those over 64.