The Boeing B-52 Stratofortress is an American long-range, high alert, subsonic, jet-powered strategic bomber.

The B-52 was designed and built by Boeing, which has continued to provide support and upgrades. It has been operated by the United States Air Force (USAF) since the 1950s.

The bomber is capable of carrying up to 70,000 pounds (32,000kg) of weapons and has a typical combat range of more than 8800 miles (14,080km) without aerial refuelling.

Beginning with the successful contract bid in June 1946, the B-52 design evolved from a straight-wing aircraft powered by six turboprop engines to the final prototype YB-52 with eight turbojet engines and swept wings. The B-52 took its maiden flight in April 1952.

Built to carry nuclear weapons for Cold War-era deterrence missions, the B-52 Stratofortress replaced the Convair B-36 Peacemaker. A veteran of several wars, the B-52 has dropped only conventional munitions in combat.

As of June 2019, there are 76 aircraft in inventory; 58 operated by active forces (2nd Bomb Wing and 5th Bomb Wing), 18 by reserve forces (307th Bomb Wing), and about 12 in long-term storage at the Davis-Monthan AFB Boneyard.

The bombers flew under the Strategic Air Command (SAC) until it was disestablished in 1992 and its aircraft absorbed into the Air Combat Command (ACC); in 2010, all B-52 Stratofortresses were transferred from the ACC to the new Air Force Global Strike Command (AFGSC).

Superior performance at high subsonic speeds and relatively low operating costs have kept them in service despite the advent of later, more advanced strategic bombers, including the Mach 2+ B-58 Hustler, the cancelled Mach 3 B-70 Valkyrie, the variable-geometry B-1 Lancer, and the stealth B-2 Spirit.

The B-52 completed 60 years of continuous service with its original operator in 2015. After being upgraded between 2013 and 2015, the last airplanes are expected to serve into the 2050s. Throughout the Cold War, B-52s and other US strategic bombers performed airborne alert patrols under code names such as Head Start, Chrome Dome, Hard Head, Round Robin, and Giant Lance.

Bombers loitered at high altitudes near the borders of the Soviet Union to provide rapid first strike or retaliation capability in case of nuclear war. These airborne patrols formed one component of the US's nuclear deterrent, which would act to prevent the breakout of a large-scale war between the US and the Soviet Union under the concept of Mutually Assured Destruction.