Dorset is a town in Bennington County, Vermont, United States. The population was 2,031 at the 2010 census. Dorset is famous for being the location of Cephas Kent's Inn, where four meetings of the Convention that signed the Dorset Accords led to the independent Vermont Republic and future statehood. Dorset is home to America's oldest marble quarry and is the birthplace of Bill W., co-founder of Alcoholics Anonymous. East Dorset is the site of the Wilson House and the Griffith Library.The East Dorset marble quarry had been established by Bill W.'s great grandfather and stayed in the family for three generations. Marble from these quarries provided stone for the New York Public Library Main Branch building in New York City. The quarry closed and during the summer months serves as a popular swimming hole.The Dorset town center is defined as the Dorset census-designated place and had a population of 249 at the 2010 census.