Willimantic is the historic seat of government for Windham County. It was incorporated from the Town of Windham in 1893. City government was dissolved in 1983, and the territory reverted to the Town of Windham. As early as 1821, Willimantic was a village (or borough), then known as Willimantic Falls.
Willimantic is an Algonquin Indian term meaning: land of the swift running water.
In the early 1800s Willimantic was known as "Thread City," referencing the American Thread Company, which operated a mill on the banks of the Willimantic River. Within a short span of less than 10 years, six cotton factories had been built in the village. American Thread moved to North Carolina about the time Willimantic consolidated with Windham.