Oak Grove is a census-designated place (CDP) in Washington County, Tennessee, United States.

[5] It is part of the Johnson City Metropolitan Statistical Area, which is a component of the Johnson City–Kingsport–Bristol, TN-VA Combined Statistical Area – commonly known as the "Tri-Cities" region.

As of the census[3] of 2000, there were 4,072 people, 1,697 households, and 1,126 families residing in the CDP.

There were 1,870 housing units at an average density of 403.7 per square mile (155.9/km2).

25.9% of all households were made up of individuals, and 4.9% had someone living alone who was 65 years of age or older.