Chagan (also known as Dolon and Semipalatinsk-2) was an air base in Semipalatinsk (modern Semey), Kazakhstan, that served as a major Cold War bomber base under the 37th Air Army, Soviet Long Range Aviation.

Until at least 1980 it served as one of three bases for the Soviet Union's Tupolev Tu-95 "Bear" long-range bomber fleet.

The nearby Dolon Southwest, a former airfield 32 km to the south, was probably a dispersal field and no longer exists.

[citation needed] In 1990, Dolon had 40 Tupolev Tu-95 (Bear) aircraft, which were eliminated by 1994, ending the base's strategic bomber role.

Units based at Dolon included: The 79th TBAD was under the control of Long Range Aviation from 1957 to 1960, the 8th independent Heavy Bomber Aviation Corps (later to become the 30th Air Army) from 1960 until 1980, and finally, the 37th Air Army from 1980 until 1992.