Bennington County is a county in the state of Vermont, in the United States. As of the 2010 census, the population was 37,125. The shire towns (county seats) are jointly Bennington ("The Southshire") and Manchester ("The Northshire"). Its largest municipality is Bennington. The county was created in 1778.
Bennington is the oldest county in Vermont still in existence, created by the first general assembly on 17 March 1778. Vermont was organized into two original counties, with Bennington in the west and Unity (a few days later renamed Cumberland) in the east. On 16 February 1781 Rutland County was created from Bennington County. On 13 April 1781 Bennington gained the gore east of the town of Bromley (now Peru) from Windham and Windsor Counties.
From 26 June 1781 until 23 February 1782, Vermont attempted to annex part of New York east of the Hudson River (the so-called West Union); inhabitants in the area favored Vermont's township form of government, while Vermont hoped to gain bargaining power through expansion. New York did not lose control of the area. For almost seven months Bennington County overlapped part of Albany County, New York.