Dyer Brook is a town in Aroostook County, Maine, United States. The population was 215 at the 2020 census. Dyer Brook is also host to the local school, Southern Aroostook Community School. According to the United States Census Bureau, the town has a total area of 38.52 square miles, of which 38.51 square miles is land and 0.01 square miles is w…Dyer Brook is a town in Aroostook County, Maine, United States. The population was 215 at the 2020 census. Dyer Brook is also host to the local school, Southern Aroostook Community School. According to the United States Census Bureau, the town has a total area of 38.52 square miles, of which 38.51 square miles is land and 0.01 square miles is water.