OVERFLAKKEE, an island of Holland, in the province of South Holland, formed by two branches of the Meuse,—the Haringvliet on the N., and the Volkerak on the S.,—and is bounded on the W. by the North Sea. A part of the island, called Goedereede, was formerly separated from Overflakkee by a branch of the river, but this has been dammed up, and the two islands united. The soil is fertile, producing wheat, barley, potatoes, &c. Length, 25 miles; greatest breadth, 7 miles. Pop. 17,000.