Dorset is a town in Bennington County, Vermont, United States. The population was 2,036 at the 2000 census. Dorset is famous for being home to America's oldest marble quarry and for being the birth place of Alcoholics Anonymnous co-founder Bill W. East Dorset is the setting of the Bill 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 3 generations. Marble from these quarries provided stone for the New York Public Library Main Branch building in New York City.