The center line on a standard ice hockey rink is red.
It runs across the middle of the rink and divides the ice into two halves. In the NHL, the center red line is also associated with icing: a puck shot from a team’s half must cross it before continuing beyond the opponent’s goal line for icing to be considered.
The center line is different from the two blue lines, which divide the rink into the attacking, neutral, and defending zones and help determine offside. The red goal lines near each net are separate markings used to judge goals and icing.
A historical mix-up comes from the former two-line pass rule. Before the NHL removed that restriction in 2005, a pass could not legally travel from behind a team’s blue line across both the center red line and the opponent’s blue line. Today, the center line remains important primarily to icing and rink orientation.