The County of Dukes County is a county located in the U.S. state of Massachusetts. Its county seat is in the Town of Edgartown. The county consists of the island of Martha's Vineyard, and the Elizabeth Islands (including Cuttyhunk). 

History

It was originally established as Dukes County, New York on November 1, 1683  when the Provincial Assembly of New York divided the province into several counties and incorporated them by name, including Kings (now Brooklyn), Queens (Long Island), and Dukes, the last being decreed to "contain the Islands of Nantucket, Martha's Vineyard, Elizabeth Island, and Noe Man's Land”.  It was transferred to Massachusetts and divided so that Nantucket Island became Nantucket County, Massachusetts on October 7, 1691. 

Name

The statute created a county "by the name of Dukes County," as opposed to the standard form "the county of Dukes" which is the reason for the redundancy in the name.

Statistics

According to the U.S. Census Bureau, the county has a total area of 491 square miles (1,272 km²), of which, 104 square miles (269 km²) of it is land and 387 square miles (1,003 km²) of it is water. The total area is 79% water.

Population

As of the latest 2024 Census Bureau estimates, Dukes County (Martha's Vineyard and Elizabeth Islands), MA, has a year-round population of approximately 20,933, reflecting a 2.3% growth since the 2020 Census. The median age is roughly 50.7 years, and the county experienced a significant 25% population increase between 2010 and 2020.