Dukes County, Massachusetts

Dukes County is a county in Massachusetts, United States, made up of Martha’s Vineyard and the smaller islands around it, in the southeastern part of the state. It had a population of 20,600 at the 2020 census and covers 491 square miles (1,270 km2) — only 103 square miles (270 km2) of that is land, the rest is water — centred near 41°25′N 70°37′W.

Edgartown is the county seat, and its postal code is 02539. The county has seven towns and no cities, villages, or CDPs with their own municipal government — every named place here is a village or neighborhood inside one of those seven towns. Dukes County sits in the Eastern time zone.

Towns & Villages in Dukes County

Massachusetts counties have no unincorporated land: all of Dukes County is divided among seven towns, six of them on Martha’s Vineyard and one, Gosnold, covering the separate Elizabeth Islands chain. The table below lists the seven towns plus the villages and named places inside them that residents and mail carriers actually use.

Two of the old settlement roll’s names don’t hold up on modern maps: Christian Town, Clevelandtown, Harthaven, Hartsville, Indian Lands, Jerneganville, Lagoon Heights, Lamberts Cove, Lobsterville, Longview, Nabs Corner, Nashaquitsa, Naushon Station, Ocean Heights, Quansoo, Suttons Mills, Tississa, Vineyard Highlands, Wepua Point, and West Opening were 19th- and early-20th-century neighborhood or landing names, most now folded into the town or village they sit inside rather than tracked as separate places. “Oklahoma Heights” is a real Oak Bluffs neighborhood name, not the state; it has been kept, moved out of the table to avoid confusion. Chappaquiddick Island (part of Edgartown) and Nomans Land Island (an uninhabited federal wildlife refuge, formerly a Navy bombing range) are real named places in the county but have no year-round population or ZIP of their own.

ZIP Codes

• 02539 — Edgartown (also serves Katama)
• 02557 — Oak Bluffs (also serves Eastville and East Chop)
• 02568 — Vineyard Haven, the year-round population center of the Town of Tisbury
• 02575 — West Tisbury (also serves North Tisbury)
• 02535 — Chilmark, and also the ZIP used for Aquinnah
• 02552 — Menemsha, a fishing village within Chilmark
• 02713 — Cuttyhunk, the only inhabited village of the Town of Gosnold

Nomans Land and Chappaquiddick have no separate ZIP; mail there is routed through Edgartown.

Geography

Dukes County has no land border with any other county — it is entirely islands in the Atlantic Ocean off the southeastern Massachusetts coast. Martha’s Vineyard, the largest island, has a mix of moraine hills in the west (Chilmark and Aquinnah’s clay cliffs at Gay Head) and outwash plain and sandy heath to the east and south. The Elizabeth Islands, administered as the Town of Gosnold, run northeast from Cuttyhunk toward Woods Hole on the mainland. Nantucket Sound lies to the north and east, Vineyard Sound and Buzzards Bay to the north and west, and the open Atlantic to the south.

Across Vineyard Sound to the north is Barnstable County (Cape Cod); Bristol County lies across Buzzards Bay to the northwest, near Gosnold; and Nantucket County lies across Muskeget Channel to the east.

Demographics

Dukes County had 20,600 residents at the 2020 census, spread across a land area of just 103 square miles — a density of about 200 people per square mile, though the population swells many times over in summer with seasonal residents and tourists. Oak Bluffs (5,341) and Edgartown (5,168) are the two largest towns; Gosnold, with 70 year-round residents, is the smallest. Median household income runs well above the Massachusetts median of $99,858 in the island’s wealthier enclaves, though year-round working households face one of the highest costs of living in the state, driven by ferry-dependent shipping and a housing market shaped by seasonal demand.

Economy & Local Life

Tourism and seasonal residency drive the county’s economy: hospitality, restaurants, real estate, and construction employ most of the year-round workforce. Commercial and recreational fishing remain active out of Menemsha and Oak Bluffs, and Martha’s Vineyard Hospital in Oak Bluffs is a major year-round employer. The Martha’s Vineyard Regional High School in Oak Bluffs serves the six island towns jointly. The Steamship Authority ferry terminals at Vineyard Haven and Oak Bluffs are the county’s lifeline for goods and visitors alike, and the annual Martha’s Vineyard Agricultural Fair in West Tisbury each August is the island’s largest community event.

History

Dukes County was organized in 1695, after an earlier Dukes County (covering Martha’s Vineyard and Nantucket together) had been established under New York’s jurisdiction in 1683 and transferred to the Massachusetts Bay colony in 1691. It is named for James, Duke of York, later King James II. Nantucket split off as its own county in 1695, and Gosnold and the Elizabeth Islands, previously attached to Chilmark, became a separate town within Dukes County in 1864. The Gay Head Wampanoag, whose reservation lands became the town of Aquinnah, have lived on Martha’s Vineyard for thousands of years and were federally recognized as the Wampanoag Tribe of Gay Head (Aquinnah) in 1987.

Getting There

Dukes County has no bridge or tunnel to the mainland — the Steamship Authority and several private ferry lines are the primary way to reach it, sailing from Woods Hole, Falmouth, Hyannis, and New Bedford. Martha’s Vineyard Airport in West Tisbury offers scheduled service to Boston and seasonal routes to New York and other cities.

• Woods Hole, Barnstable County — 7 miles north (ferry crossing)
• Hyannis, Barnstable County — 20 miles northeast (ferry crossing)
• New Bedford, Bristol County — 12 miles northwest (ferry crossing to Gosnold/Cuttyhunk)
• Nantucket — roughly 20 miles east across Muskeget Channel (seasonal ferry)

The nearest major commercial airport is Boston Logan International, about 75 miles north by air or a combined ferry-and-drive route.

Frequently Asked Questions

Where is Dukes County, Massachusetts?
It covers Martha’s Vineyard and the Elizabeth Islands, off the southeastern Massachusetts coast, reachable only by ferry or small aircraft.

What is the population of Dukes County?
20,600 at the 2020 census, though the summer population is far higher with seasonal residents and visitors.

How big is Dukes County?
491 square miles in total, but only 103 square miles is land — the rest is the surrounding water.

What is the county seat of Dukes County?
Edgartown.

How many towns are in Dukes County?
Seven: Edgartown, Oak Bluffs, Tisbury, West Tisbury, Chilmark, and Aquinnah on Martha’s Vineyard, plus Gosnold on the Elizabeth Islands.

What ZIP codes are in Dukes County?
02539 (Edgartown), 02557 (Oak Bluffs), 02568 (Vineyard Haven/Tisbury), 02575 (West Tisbury), 02535 (Chilmark and Aquinnah), 02552 (Menemsha), and 02713 (Cuttyhunk/Gosnold).

Does Dukes County have any cities?
No. All seven of its municipalities are legally towns, governed by open town meeting, not cities.

More counties in this state: Towns and villages in Massachusetts.