Aroostook County is a county in the U.S. state of Maine along the Canada–United States border. As of the 2020 census, the population was 67,105. The county seat is Houlton, with offices in Caribou and Fort Kent. Known in Maine as "The County", it is the largest county in Maine by total area, the second-largest in the United States east of the Mississippi River by total area, and the 31st-largest county in the entire contiguous U.S. With over 6,800 square miles of land; it is larger than three of the smaller U.S. states.