Dry Tortugas National Parkis an American national parklocated about 68 miles west of Key Westin the Gulf of Mexico, in the United States. The park preserves Fort Jeffersonand the severalDry Tortugasislands, the westernmost and most isolated of the Florida Keys. The park area is more than 99 percent water. It is noted for abundant sea life, tropical bird breeding grounds, colorful coral reefs, shipwrecksand sunken treasures. The park's centerpiece is Fort Jefferson, a massive but unfinished coastal fortress. Fort Jefferson is the largest brick masonrystructure in the Western Hemisphere,composed of more than 16 million bricks. Dry Tortugas is unique in its combination of a largely undisturbed tropical ecosystem with significant historic artifacts. The area was established as a national park on January 4, 1935.