Pituffik Space Base ( bee-doo-FEEK; Greenlandic: [pitufːik]) (IATA: THU, ICAO: BGTL), formerly Thule Air Base ( or ), is the United States Space Force's northernmost base, and the northernmost installation of the U.S. Armed Forces, located 750 mi (1,210 km) north of the Arctic Circle and 947 mi (1,524 km) from the North Pole on the northwest coast of the island of Greenland. Pituffik's Arctic environment includes icebergs in North Star Bay, two islands (Saunders Island and Wolstenholme Island), a polar ice sheet, and Wolstenholme Fjord – the only place on Earth where four active glaciers join. The base is home to a substantial portion of the global network of missile warning sensors of Space Delta 4, and space surveillance and space control sensors of Space Delta 2, providing space awareness and advanced missile detection capabilities to North American Aerospace Defense Command (NORAD), the United States Space Force, and joint partners.

Pituffik Space Base is also home to the 821st Space Base Group and is responsible for space base support within the Pituffik Defense Area for the multinational population of "Team Pituffik". The base hosts the 12th Space Warning Squadron (12 SWS) which operates a Ballistic Missile Early Warning System (BMEWS) designed to detect and track ICBMs launched against North America. The base is also host to Detachment 1 of the 23rd Space Operations Squadron, part of the Space Delta 6's global satellite control network. The airfield's 10,000-foot (3,000 m) runway handles more than 3,000 US and international flights per year. The base is also home to the northernmost deep water port in the world.

Pituffik Space Base has served as the regional hub for nearby installations, including Cape Atholl (LORAN station), Camp Century (Ice Cap Camp), Camp TUTO (Ice Cap Approach Ramp and Airstrip), Sites 1 and 2 (Ice Cap Radar Stations), P-Mountain (radar and communications site), J-Site (BMEWS), North and South Mountains (research sites), and a research rocket firing site. It also was essential in the construction and resupply of High Arctic weather stations, including CFS Alert (Alert Airport) and Station Nord.