The Western District Army (西部方面軍, Seibu-hōmen gun) was a regional command of the Imperial Japanese Army (equivalent to a field army) responsible for the defense of the Kantō region and western Honshū, Shikoku and Kyūshū during the Pacific War.
The Western District Army was established on 2 August 1937 as part of the regional realignment of the Imperial Japanese Army as the Western Defense Command (西部防衛司令部, Seibu Boei Shireibu).
It was essentially a home guard and garrison responsible for recruitment and civil defense.
The Western District Army existed concurrently with the Japanese 16th Area Army and the Japanese 15th Area Army, which were tasked with organizing the final defenses of Kyūshū and Shikoku against the expected American invasion of the Japanese home islands.
The Western District Army remained active for several months after the surrender of Japan to help maintain public order until the arrival of the American occupation forces, and to oversee the final demobilization and dissolution of the Imperial Japanese Army.