Key West is often referred to as "Mile 0" due to its location at the southernmost point of U.S. Route 1, which runs along the East Coast of the United States. The designation "Mile 0" signifies the starting or ending point of U.S. Route 1, depending on the direction of travel.
U.S. Route 1 is a major north-south highway that spans over 2,300 miles, connecting Key West in Florida to Fort Kent in Maine. The mileage along U.S. Route 1 is measured from north to south, and Key West is at the southern terminus of this iconic highway.
The "Mile 0" marker, located in Key West, is a popular photo spot for visitors, signifying the beginning or end of their journey along U.S. Route 1, depending on the direction they are traveling. It has become an iconic symbol, and the marker itself is often adorned with various decorations and markings. The southernmost point in Key West is also marked by a buoy, which is another famous landmark and a popular tourist attraction.