Union is a town located in the northeastern part of Tolland County, Connecticut, United States and is part of the Quinebaug and Shetucket Rivers Valley National Heritage Corridor. The population was 785 at the 2020 census, making it the least populous town and municipality in Connecticut. Union includes the village of Mashapaug located in the Eastern Uplands at the Massachusetts state line. Union is located northeast of the state capital, Hartford and southwest of Boston as well as northeast of New York City. History The first European Settlement in Union was in 1727, making Union the last Connecticut town east of the Connecticut River to be settled. The first settler was James McNall of Ireland. He was closely followed by his brother William. The town was incorporated in October 1734. The name Union designates "union of lands". Union was first a town in Windham County. It became a town in Tolland County upon its formation from part of Windham County on 13 October 1785. There were 500 people in the town in 1756. The population grew to 767 by 1800, but declined thereafter. There were just 431 people in Union in 1890. The official population of the town is still less than 1,000 residents today. Civic associations Union is home to Venturing Crew 83 of the Connecticut Rivers Council. They are a member of the Nipmuck District and chartered by the Union Volunteer Fire Department. Geography According to the United States Census Bureau, the town has a total area of , of which is land and (3.75%) is water. Union has the highest town center in eastern Connecticut at and the 4th highest in the state. The highest elevation in eastern Connecticut is Burley Hill in the northwest part of town. In addition, I-84 reaches its highest elevation in Connecticut () in Union. Approximately one-third of the town is state park land, including Bigelow Hollow State Park, Nipmuck State Forest and the Mountain Laurel Sanctuary. A portion of the Yale-Myers Forest and Hull Foresters are located in Union. All combined, there are nearly 34,000 acres of forestland in Union. Mashapaug Lake is a large lake in Union. The lake is used for fishing, boating, and swimming. Demographics At the census of 2000, there were 693 people, 285 households, and 200 families residing in the town. The population density was 24.1 people per square mile (9.3/km). There were 332 housing units