Appalachian Trail (AT) is 2,155 mile long (2,138 miles in 1990).
The AT passes through 14 States beginning with Maine followed by New Hampshire, Vermont, Massachusetts, Connecticut, New York, New Jersey, Pennsylvania, Maryland, West Virginia, Virginia, Tennessee, North Carolina, and finally Georgia.
The 2,650 mile Pacific Crest Trail (PCT), was one of the first trails approved by Congress in 1993, under the National Trails System Act of 1968.
The PCT begins at the US/Mexico border near Campo, California, and ends at its northern terminus at Monument 78 in Washington at the US/Canada border.
The 3,100 mile Continental Divide Trail (CDT), was established by Congress in 1978, under the National Trails System Act of 1968.
The CDT begins for south bounding hikers at the US/Canada border in Glacier National Park. The trail goes through Montana, Idaho, Wyoming, Colorado, New Mexico and ends at the US/Mexico border.