The North Warning System (NWS) is a joint United States and Canadian radar system for the atmospheric air defense of North America. It provides surveillance of airspace from potential incursions or attacks from across North America's polar region. It replaced the Distant Early Warning Line system in the late 1980s.

The NWS consists of both long AN/FPS-117 and short range AN/FPS-124 surveillance radars, operated and maintained by the North American Aerospace Defense Command (NORAD). The Alaska Regional Operations Control Center (ROCC) at Elmendorf AFB, Alaska controls the stations in Alaska; the Canada East and Canada West Regional Operations Control Centers (ROCCs) at CFB North Bay, Ontario control the stations in Canada. ROCC information is then passed to the North American Air Defense Command (NORAD) Combat Operations Centre (COC) at Colorado Springs, Colorado.

The Distant Early Warning Line, constructed in the late 1950s, was reaching obsolescence in the 1980s. With the signing of North American Air Defence Modernization agreement at the "Shamrock Summit" between Prime Minister Mulroney and President Reagan in Quebec City on 18 March 1985 the DEW Line began it's eventual upgrading and transition becoming the North Warning System (NWS) of today.

The NWS began limited operation in 1988 with the commissioning and acceptance of the three newly constructed east coast sites BAF-3 Brevoort Island NUNAVUT, LAB-2 Saglek, and LAB-6 Cartwright both in Labrador. Throughout the late 1980s and early 1990s, new NWS LRR radars replaced former DEW Line sites. DEW sites that weren't transitioned to North Warning operation were eventually closed down. The official activation of the NWS and inactivation of the DEW Line took place on 15 July 1993.

The bi-national North Warning System Office (NWSO) is located in Ottawa, Ontario and staffed with both Canadian and American military and civilian personnel. Manned sites are operated by the Canadian Forces Air Command. Logistical and maintenance support for the NWS is supplied by the United States Air Force Materiel Command, Ogden Air Logistics Center (OO-ALC), Hill Air Force Base, Utah.

The NWS consists of 15 long-range radars (11 in Canada of which 8 were DEW Line sites) and 39 short-range radars (36 in Canada).^[1] The system forms a 4,800-kilometer-long and 320-kilometer-wide "tripwire" stretching from Alaska, via Canada, to Southern Labrador.

• List of Canadian Forces Bases
• Operation Hurricane (Canada)
• Joint Surveillance System
• NORAD Tracks Santa Program

• About NORAD Public information.
• PAIL Corp. Public information from PAIL Corp.
• Technical Radar Information NWS Radar information from FAS.