AllTrails categorizes each trail using three different route types:
Loop trails start and end at the same location and follow a single trail or multiple trails to form a loop.
Out-and-Back trails start and end at the same location and follow a single trail or multiple trails to an end point and then return along the same route.
Point-to-Point trails start and end in different locations. These routes are often part of a multi-day hiking or backpacking trip or segments of a long distance trail such as the Appalachian Trail or Pacific Crest Trail.
NOTE: All trail distances provided are for the total length of the mapped route. For example, a 10 mile loop, or out-and-back trail, is 10 miles total from start to finish.