The Farmington River is a river, in length along its main stem, located in northwest Connecticut with major tributaries extending into southwest Massachusetts. The longest route of the river, from the origin of its West Branch, is long, making it the Connecticut River's longest tributary by over the major river directly to its north, the Westfield River. The Farmington River's watershed covers . Historically, the river played an important role in small-scale manufacturing in towns along its course, but it is now mainly used for recreation and drinking water. Geography Headwaters for the two branches of the Farmington River, the East Branch and West Branch, are found in southwestern Massachusetts, though only the West Branch officially begins north of the Connecticut border. The West Branch begins at the outlet of Hayden Pond in Otis, Massachusetts. The East Branch begins in Hartland, Connecticut at the confluence of Pond, Hubbard and Valley Brooks. However, this branch has been impounded along the first 11 miles of its course to form the Barkhamsted Reservoir and Lake McDonough; it does not assume a river-like appearance until it exits Lake McDonough in New Hartford, Connecticut. The East Branch and West Branch join in New Hartford, Connecticut, one mile south of the lake. Upper reaches of the river generally flow southward, but the river turns northward in Farmington, Connecticut, and runs mostly north and east until it flows into the Connecticut River in Windsor. History Sites built adjacent to the river by nomadic peoples at the end of the last Ice Age, 12,400 years BP of the Younger Dryas indicate the presence of the earliest peoples to populate the region that would become known as southern New England. In the winter of 2019, the remains of the site were excavated in Avon, along with stone tools and artifacts constructed from materials in neighboring regions. The upper Connecticut and Farmington River valleys were the lands of the Native American indigenous people called the Massaco, a sub-tribe of the Tunxis, who were affiliated with the Wappinger. The name Tunxis, a word in the Quiripi family of Eastern Algonquian languages, derives from the indigenous term Wuttunkshau for "the point where the river bends". Halfway through the course of the river, in a floodplain in the town of Farmington at the base of the Metacomet Ridge, the flow of the Farmington River changes its direction to the northeast, where it eventually