Getting lost in the Keys is almost impossible once you understand the unique address system. Many addresses are simply given as a mile marker (MM) number. The markers are small, green, rectangular signs along the side of the Overseas Highway (U.S. 1). They begin with MM 126, 1 mi south of Florida City, and end with MM 0, in Key West. Keys residents use the abbreviation BS for the bay side of U.S. 1 and OS for the ocean side. From Marathon to Key West, residents may refer to the bay side as the gulf side. More »
