Limestone is a town in Aroostook County, Maine, United States. The population was 1,526 at the 2020 census. The town is best known for being the home of the Loring Commerce Centre (formerly Loring Air Force Base; also lying on its former territory is the Aroostook National Wildlife Refuge) and Maine School of Science and Mathematics (MSSM), which in 2019 ranked #2 in the United States by U.S. News & World Report. The population center of the town is in Limestone (CDP), in the east-central part of the town.