A set of markings in the center of the field that assists the officials in spotting the ball after a play. The hash marks are a pair of dotted lines running parallel to the sideline equidistant from each sideline. If a play ends outside the hash marks, the ball is to be spotted on the outside edge of the hash mark parallel to the point where play stopped. Inside the hash marks, the ball is spotted at the point of the dead ball.
The hash marks are used for spotting the ball, as well as an indicator for officials on where certain infractions are taking place. For instance, the hash marks help the officials keep track of whether the quarterback is in the pocket or not. The hash marks also help designate whether a running back is running "inside" or "outside". Runs that go outside of the hash marks are considered to be "outside" runs. The hash marks make up a dotted line to avoid confusion with other lines on the field.