[3] Black Rock is located in northern Lawrence County at 36°6′28″N 91°5′56″W / 36.10778°N 91.09889°W / 36.10778; -91.09889 (36.107794, -91.098913),[4] at the eastern edge of the Ozarks.

Routes 63 and 412 run concurrently through the south side of the city, leading northwest 30 miles (48 km) to Hardy.

There were 334 housing units at an average density of 101.8 per square mile (39.3/km2).

The racial makeup of the city was 99.02% White, 0.14% Native American, and 0.84% from two or more races.

28.2% of all households were made up of individuals, and 12.7% had someone living alone who was 65 years of age or older.