The settlement of Colbyville includes the area from the foot of Blush Hill northward on Route 100. It currently contains a mixture of residences, commercial services, and manufacturing facilities.
The area was first settled in 1788. Upper and lower falls in Colbyville provided power for several mill and manufacturing operations through the 1800’s. Historical records suggest that the Colby mills were probably the first large mills in Waterbury. A schoolhouse once stood at the current site of a gas station. In the 1940’s, the Colby Mansion was the Colby Private Hospital for the elderly; it is now used as an office building.