The A.T. is marked for daylight travel in both directions using a system of white "blazes," or a rectangle of white paint 2 inches wide and 6 inches high. Blazes are found on trees, posts and rocks. Posts and rocks called "cairns" are also used to identify the route in some places. Side trails and shelter trails use blue blazes, and blazes of other colors and shapes mark other intersecting trails.
Distance between blazes varies. If you have gone as much as a quarter-mile without seeing a blaze, stop. Retrace your steps until you locate a blaze. Then, check to make sure you haven't missed a turn. When your map or guidebook indicates one route, and the blazes show another, follow the blazes.
In wilderness areas (found in areas from Georgia to Virginia and in Vermont and New Hampshire) blazing is intentionally much less frequent and signage is minimal to retain the wilderness character of the land. Side trails may not be marked. Carrying a map and compass are especially important in these areas.
In areas of historic significance, which include Harpers Ferry National Historical Park in West Virginia and the C&O Canal National Historical Park in Maryland, blazing and signage may be less frequent or less prominent.