[2] Dukes County comprises the Vineyard Haven, MA Micropolitan Statistical Area.

The county consists of 32 named islands,[3] the largest of which is Martha's Vineyard.

Political jurisdiction over the lands were granted by the English monarchy in overlapping claims to two different British nobles, from which Massachusetts Bay Company settler Thomas Mayhew purchased them in 1641.

Mayhew established a colony in his new domain, carefully purchasing land ownership rights from the native inhabitants, and maintaining native governments to continue unimpeded.

In 1671, a settlement was arranged, allowing Mayhew to continue to rule while placing his territory under the jurisdiction of the Province of New York.

Dukes County was thus established as Dukes County, New York, on November 1, 1683, and included all of Mayhew's lands – Martha's Vineyard, Nantucket, and the Elizabeth Islands.

20.4% were of English, 13.3% Irish, 8.6% Portuguese, 6.4% Italian and 5.7% American ancestry, 93.1% spoke English, 3.7% Portuguese and 1.7% Spanish as their first language and 0.285% speak Irish at home.

As of the fourth quarter 2021, the median value of homes in Dukes County was $883,820, an increase of 22.3% from the prior year.

[21][22][23] As does the rest of the state of Massachusetts, Dukes County heavily supports the Democratic Party.

Before 1964, however, the county was a stronghold of the Republicans, supporting Dwight D. Eisenhower in 1956 by an especially large margin, well over 50%, and was one of the few counties where William Howard Taft finished ahead of Woodrow Wilson in 1912.