How large is Martha’s Vineyard? Martha’s Vineyard is approximately 96 square miles, roughly triangular in shape, 25 miles (42k) at it’s longest point east to west, and 9 miles (12.8k) at the longest point north to south. No, in fact there are 6 distinctive towns on the Vineyard, each with its own character, flare, attractions, dining, lodging and more.