The Appalachian Trail (the A.T.), is a hiking trail in the Eastern United States, extending almost 2,200 miles (3,540 km) between Springer Mountain in Georgia and Mount Katahdin in Maine, and passing through 14 states. The Appalachian Trail Conservancy claims the Appalachian Trail to be the longest hiking-only trail in the world. More than three million people hike segments of the trail each year. The trail was first proposed in 1921 and completed in 1937 after more than a decade of work. Improvements and changes have continued since then. It became the Appalachian National Scenic Trail under the National Trails System Act of 1968.