Locust Grove is a city in Henry County, Georgia, United States. The population was 5,402 at the 2010 census, up from 2,322 in 2000. Some unincorporated communities such as Luella and many rural areas surround Locust Grove, and those communities have Locust Grove postal addresses.Locust Grove has experienced a growth in population and in businesses coming into the area. In 1900 the population of the city was 254 and is now over 5,000.