Iruma Air Base
Iruma Air Base is a principal Japan Air Self-Defense Force (JASDF) facility located in Sayama, Saitama Prefecture, Japan, roughly 40 kilometers northwest of Tokyo, serving as a hub for air defense operations and support functions in the greater metropolitan area.[1][2] Established in 1937 as Irumagawa Airfield to train personnel for the Imperial Japanese Army Air Force, the site functioned as a flight academy until the end of World War II, after which United States forces occupied it and redesignated it Johnson Air Base for logistical and maintenance roles supporting regional operations.[3][4] Returned to Japanese administration in 1958, it transitioned into a JASDF installation focused on territorial airspace surveillance and defense.[5] The base now hosts the headquarters of the Central Air Defense Force, along with units such as the 2nd Tactical Airlift Group operating C-130J transport aircraft and the Flight Check Squadron maintaining YS-11FC flight inspection planes, contributing to Japan's around-the-clock aerial warning and control missions.[6][7][8] It also features an annual air festival that showcases JASDF capabilities to the public and fosters bilateral military ties through regular exchanges and joint exercises with U.S. forces stationed nearby.[9]Geography and Infrastructure
Location and Accessibility
Iruma Air Base is located in Sayama, Saitama Prefecture, Japan, approximately 40 kilometers northwest of central Tokyo by road, positioning it for swift access to the densely populated Kanto region.[10] The base's coordinates are 35°50′03″N 139°24′39″E, placing it within a suburban landscape conducive to aviation activities amid surrounding residential and agricultural areas.[11]
At an elevation of 91 meters above sea level, the site's topography supports standard flight operations with minimal adjustments for altitude-related factors such as air density.[11] Accessibility for ground logistics is enhanced by proximity to the Kan-Etsu Expressway, accessible via the Tokorozawa interchange, and National Route 463, enabling efficient vehicular transport of personnel and materiel from Tokyo and beyond.[12] Rail connectivity is provided through Sayamashi Station on the Seibu Ikebukuro Line, approximately 3 kilometers away, offering direct links to central Tokyo in under an hour.[13] This infrastructure reduces dependence on air or sea routes, bolstering operational resilience.[14]