Windham County is a located in the northeastern corner of Connecticut. The entire county is within the Quinebaug and Shetucket Rivers Valley National Heritage Corridor, as designated by the National Park Service. There are no incorporated cities in Windham County. There is one incorporated borough, Danielson. The county has a total area of 521 square miles of which approximately 98.5% is land and 1.5% water. As of 2000, the population was 109,091 in Windham County.