Dukes County, Massachusetts: History
The original inhabitants of the islands were Wampanoag, who had several villages. 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 1665, Mayhew's lands were included in a grant to James, Duke of York (later King James II). 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. The county was transferred to Massachusetts on October 7, 1691, and at the same time Nantucket Island was split into the separate Nantucket County, Massachusetts. The 1695 incorporation 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 formal name, "County of Dukes County".