Monroe County is a county with an estimated population of 74,737 as of 2006. Its county seat is Key West, but it also includes Key Colony Beach, Layton, Marathon and all the islands of the Florida Keys. Monroe County was created in 1823 and named for James Monroe, fifth President of the United States. The county has a total area of 3,737 square miles, of which 73.32% is water. More than 99.9% of the Monroe County population lives in the island chain known as the Florida Keys. Two thirds of a large area also known as "mainland Monroe" is protected by the Everglades National Park and the rest by the Big Cypress National Preserve in the northeastern interior. The area is named Cape Sable Census County Division is virtually uninhabited. This area had 86.9% of the county's land area but only 60 residents. The area is also known as Census Tract 9701 of Monroe County.