The Western Region came into existence on January 1, 1973. It roughly replaced BSA Region 11 and BSA Region 12. At the time, the Western Region was one of 6 Regions in the BSA.
In 1993, the BSA consolidated down to 4 Regions, and the Western Region was expanded to include parts of BSA Region 8, BSA Region 9, and BSA Region 10.
The original office for the Western Region was in Sunnyvale, California, before it moved to Tempe, Arizona, in the early 1990s. In latter years, Regional offices were closed in favor of direct management from the BSA National Office in Irving, Texas.
In 2022, the BSA was reorganized into National Service Territories (now Council Service Territories), and the Regional system ceased to exist from there.