Chappaquiddick Island is a small island off the eastern end of the larger island of Martha's Vineyard. The two islands are connected, along their southern coast, by a narrow barrier beach accessible only by four-wheel-drive vehicles. A small, barge-like ferry shuttles between Chappaquiddick and the town of Edgartown, Massachusetts on Martha's Vineyard proper, carrying cars and passengers.
Geographically, Chappaquiddick is considered an island, despite the fact that it becomes entirely separate only when storms breach the barrier beach. Politically, it is part of the town of Edgartown in Dukes County. Socially, its residents form a tight-knit community and see themselves as distinctly separate from the rest of Edgartown. Long-time residents speak of "going to the mainland" when they travel to Edgartown, and of "going to America" when (for example) they travel to Boston or Providence, Rhode Island.
In July 1969 Chappaquiddick achieved national notoriety when (well after midnight) Sen. Edward Kennedy, drove his car off Dyke Bridge -- a one-lane wooden structure that links Chappaquiddick to the barrier beach that forms its eastern shore. The car overturned as it left the bridge, landing upside down in a fast-moving tidal stream known as "the Dyke." Kennedy swam free, but his passenger, a young staffer named Mary Jo Kopechne, was trapped in the car and drowned.
The accident quickly blossomed into a scandal. Kennedy was criticized for failing to come to Kopechne's aid, for failing to summon help, and for waiting until the following morning to report the accident to authorities. Allegations that Kennedy had been drunk, that he had lied about the accident, and that he had intended to have sex with Kopechne were widely reported and discussed. The accident permanently stained Kennedy's political career, and may have cost him a serious chance at the presidency.
A grand jury convened in Edgartown several months after the accident declined to issue an indictment against Kennedy. The decision, though consistent with Massachusetts law, led critics to charge that the Kennedy family had used its power to ensure a favorable verdict.