Derby is a town in Orleans County, Vermont, United States. The population was 4,604 at the 2000 census. The town contains four unincorporated villages: Beebe Plain, Clyde Pond, Lake Salem and North Derby; and two incorporated villages: Derby Center and Derby Line.
The northernmost town located along Interstate 91, the Town of Derby encompasses the largest area in Orleans County. As of the 2010 censuses, Derby surpassed the city of Newport to also become the most-populous community in the county.
According to the United States Census Bureau, the town has a total area of 57.6 square miles (149.2 km2), of which 49.6 square miles (128.5 km2) is land and 8.0 square miles (20.7 km2) (13.87%) is water. The town lies in the northernmost part of Orleans County, forming part of Vermont's border with Canada, and is otherwise bordered to the east by Holland, the southeast by Morgan and Charleston, the southwest by Coventry and Brownington, and to the west by Lake Memphremagog.
Lake Salem is within the town boundaries. Clyde Pond was formed by damming the Clyde River.
Derby is represented by Loren Shaw (R-Derby, elected 2012) and Lynn Batchelor (R-Derby Line, elected 2010) in the Orleans-1 district of the Vermont House of Representatives. It is represented by John S. Rodgers (D-Glover, elected 2012) and Robert Starr (D-North Troy, elected 2004) in the Essex-Orleans district of the Vermont Senate.
On October 29, 1779, the state of Vermont chartered it to Timothy Andrus and fifty-nine associates, with an area of 23,040 acres (93.2 km2).