Danby is a town in Rutland County, Vermont, United States. The population was 1,311 at the 2010 census.
According to the Vermont Encyclopedia, Danby was most likely named for Thomas Osborne, Earl of Danby and Duke of Leeds. However, Henry Gannett in 1905 attributed the town's name to Danby, North Yorkshire, in England. Historian Willard Sterne Randall, in his biography of Ethan Allen, gives yet another name origin: that Allen named Danby "after the French Naval commander whose fleet invaded New England's waters in the French and Indian War."
According to the United States Census Bureau, the town has a total area of 41.5 square miles (107 km2), of which 41.4 square miles (107 km2) is land and 0.1 square miles (0.26 km2), or 0.22%, is water.
Most of the town lies in Taconic Mountains; the eastern boundary of the town generally follows the course of Otter Creek in the narrow Valley of Vermont. Dorset Peak, part of the Taconic range, lies on the town's southern border and reaches an elevation of 3,804 feet. Danby quarry, located near the peak, opened in the early 20th century and is likely the world's largest underground marble quarry. It was reported in 2001 to have a total monthly output of about 1,200 tons of marble, half of which consists of Imperial Danby, a fine architectural marble with a variety of uses. Danby marble has been used in a number of notable buildings, including the United States Supreme Court building and the Jefferson Memorial.
As of the census of 2000, there were 1,292 people, 502 households, and 362 families residing in the town. The population density was 31.2 people per square mile (12.0/km2).