Walnut Grove is a census-designated place in Sumner County, Tennessee, United States.

It disincorporated on July 1, 2001, after the law under which it had incorporated was ruled unconstitutional.

[8] According to the United States Census Bureau, Walnut Grove had a total area of 4.8 square miles (12 km2), all of it land.

There were 249 housing units at an average density of 74.4 per square mile (28.7/km2).

13.3% of all households were made up of individuals, and 6.2% had someone living alone who was 65 years of age or older.