Brattleboro, originally Brattleborough, is a town in Windham County, Vermont, United States, located in the southeast corner of the state, along the state line with New Hampshire. The population was 12,049 at the 2010 census. It is situated along the Connecticut River, at the mouth of the West River.

Brattleboro is the oldest town in the state of Vermont and is noted for its vibrant arts community. The town is home to the respected Brattleboro Retreat, a psychiatric hospital and convalescent center, and the SIT Graduate Institute, a renowned graduate educational institution.

Once known as "Wantastiquet", the area where Brattleboro lies is at the confluence of the West River and the Connecticut River. The West River was called Wantastiquet in the Abenaki language, a word meaning "river which leads to the west", and is marked by Mount Wantastiquet at its mouth and the Wantastiquet Ponds at its source. The Abenaki would transit this area annually between Missisquoi (their summer hunting grounds} in northwestern Vermont, and Squakheag (their winter settlements) near what is now Northfield, Massachusetts. The band of Abenaki who frequented this area were called Sokoki, which means "people who go their own way" or "people of the lonely way". The Abenaki vigorously defended their land, which they called "Ndakinna," against European settlement in the 17th and 18th centuries (and especially during Dummer's War). Because the Abenaki had sided with the French in the mid-1700s, most of them were driven north into Quebec, opening the way for British – and later American – settlements in the area.