from the NFHS rule book
It is forward-pass interference if any player of A or B who is beyond the neutral zone interferes (to interpose in a way that hinders or impedes: come into collision) with an eligible opponent's opportunity to move toward, catch or bat the pass or hinders an opponent’s vision with out making an attempt to catch, intercept or bat the ball, even though no contact was made. There is no “5-yard bump and run” rule in High School Football. The pass being uncatchable has no bearing on the ruling of pass interference. Both receiver and defender have the right to catch the ball. An offensive receiver on his line may contact the defender across the line from them but, contact must terminate before traveling more than 2 yards down field if the ball is thrown across the line of scrimmage. Offensive receivers need to avoid contact with all defensive players as defenders are eligible receivers also. Any blocking down field by an offensive player is Offensive Pass interference if the ball crosses the line of scrimmage. A defensive player must avoid contact with a receiver who is no longer a potential blocker. So a receiver is a potential blocker until there is a pass. A defender can contact an offensive receiver until the ball is thrown. All plays are running plays until the ball is passed. Pass interference on the defense can only happen in the area of the field where the ball is thrown. Anywhere else on the field the contact with an eligible receiver is Illegal use of hands, holding or a personal foul. Incidental and unavoidable contact is not a foul. If a defender and receiver get their feet tangled, it is not a foul. If players are backing up to position them selves to catch a pass and bump into an eligible receiver, is not a foul. Use good judgment in determining if contact impeded or prevented a receiver or defender from moving toward, catching, intercepting or batting the ball.
