Hash marks mark each yard line 70 feet, 9 inches from the sidelines in the NFL. On high school and college football fields, the hash marks are only 60 feet from the sidelines. Two sets of hash marks (each hash is 1 yard in length) run parallel to each other down the length of the field and are approximately 18% feet apart. When the ball carrier is either tackled or pushed out of bounds, the officials return the ball in bounds to the closest hash mark.
Punted balls that go out of bounds are also marked on the nearest hash mark.