Small
island in the
Chesapeake Bay, approximately halfway between
Virginia's
Northern Neck and
Eastern Shore.
The island has been settled since the earliest days of British colonization of the Americas. However, its severe isolation (there are no bridges to the mainland, and ferries' docking points are ~2 hours away from the nearest major metro area) generated a very insular culture, and a distinctive accent that has barely changed since the seventeenth century settlers arrived (as mentioned in heyoka's WU on the origins of the American accent). Fishing was historically the island's most productive industry, but tourism trumps that these days.
The last name Crockett is very common on Tangier, which leads people to ask me whether I have family there. I don't; the fact of the matter is that natives of Tangier rarely leave the island for good, so if you run across a Crockett with a fairly conventional accent of any sort, he/she is not likely to be from Tangier.