Throughout its history, the town has been home to a Wampanoag community, which gained federal recognition in 1987 and controls tribal lands in the town.
Aquinnah is separated from the town of Chilmark by Menemsha Bight, Menemsha Pond, and Squibnocket Pond, and the only road into town lies between the ponds. (Squibnocket Beach, which lies between the ocean and Squibnocket Pond, also connects to the town, but is often washed out during storms, and there is no road crossing it.) Squibnocket Point, just east of this beach, is the southernmost point on Martha's Vineyard. Aquinnah has four beaches: Philbin Beach (residents only) and Moshup Beach to the southwest, Long Beach (adjacent to Squibnocket Beach but privately owned), and Lobsterville Beach along the Sound side of town. The Gay Head Cliffs are in a protected area at the western end of town, where the Gay Head lighthouse stands.
There is no direct transit between Aquinnah and the mainland; Martha's Vineyard Airport is in nearby West Tisbury, and the Woods Hole Ferry is in Vineyard Haven, approximately seventeen miles from the town center.
There were 141 households out of which 33.3% had children under the age of 18 living with them, 38.3% were married couples living together, 17.7% had a female householder with no husband present, and 36.9% were non-families. 30.5% of all households were made up of individuals and 7.8% had someone living alone who was 65 years of age or older. The average household size was 2.44 and the average family size was 3.04.
In the town the population was spread out with 25.3% under the age of 18, 8.7% from 18 to 24, 31.7% from 25 to 44, 24.1% from 45 to 64, and 10.2% who were 65 years of age or older. The median age was 37 years. For every 100 females there were 96.6 males. For every 100 females age 18 and over, there were 84.9 males.
The median income for a household in the town was $45,208, and the median income for a family was $46,458. Males had a median income of $37,917 versus $26,250 for females. The per capita income for the town was $21,420. About 8.6% of families and 7.1% of the population were below the poverty line, including 4.0% of those under age 18 and 14.3% of those age 65 or over.
On the state level, Aquinnah is represented in the Massachusetts House of Representatives as a part of the Barnstable, Dukes and Nantucket district, which includes all of Martha's Vineyard and Nantucket, as well as a portion of Falmouth. The town is represented in the Massachusetts Senate as a portion of the Cape and Islands district, which includes all of Martha's Vineyard, Nantucket and most of Barnstable County (with the exception of Bourne, Sandwich, Falmouth and a portion of Barnstable.. All of Dukes County is patrolled by the Fifth (Oak Bluffs) Barracks of Troop D of the Massachusetts State Police.
Aquinnah is governed on the local level by the open town meeting form of government, and is led by an executive secretary and a board of selectmen. The town has its own police and fire departments, near the Town Hall at the town center. The post office is also nearby, as is the Aquinnah Public Library, a one-room library of less than 1,000 square feet. Actually the post office is located 8 miles away in Chillmark.