Locust Grove is a town in Mayes County, Oklahoma, United States. The population was 1,423 at the 2010 census, a 4.2 percent decline from 1,366 at the 2000 census.

Locust Grove is located at 36°11′50″N 95°10′1″W / 36.19722°N 95.16694°W / 36.19722; -95.16694 (36.197290, -95.166993).

According to the United States Census Bureau, the town has a total area of 0.9 square miles (2.3 km²), all of it land.

As of the census of 2010, there were 5,200 people, 819 households, and 363 families residing in the town. The population density was 1,606.7 people per square mile (620.5/km²). There were 567 housing units at an average density of 666.9 per square mile (257.6/km²). The racial makeup of the town was 57.32% White, 32.50% Native American, 0.22% Asian, 0.81% from other races, and 9.15% from two or more races. Hispanic or Latino of any race were 2.42% of the population.

There were 519 households out of which 38.9% had children under the age of 18 living with them, 47.4% were married couples living together, 17.7% had a female householder with no husband present, and 29.9% were non-families. 26.8% of all households were made up of individuals and 16.0% had someone living alone who was 65 years of age or older. The average household size was 2.63 and the average family size was 3.14.