Locust Grove is an unincorporated community in Adams County, Ohio, United States. Locust Grove is located at the junction of Ohio State Route 41 and Ohio State Route 73 north-northeast of Peebles.
Locust Grove was laid out in 1835. The community was named for a grove of locust trees near the original town site. A post office was established at Locust Grove in 1833, and remained in operation until 1920.