The U.S. Army Reserve Birthday is celebrated annually on April 23 to honor the contributions of the Army Reserve to various conflicts, including the World Wars, the Cold War, and the Persian Gulf. This federal reserve force, which has been active for over a century, plays a crucial role in U.S. military history and has units in all 50 states, 20 time zones, and five U.S. territories. The Army Reserve was established in 1908 with the formation of the Medical Reserve Corps and has since evolved to include trained soldiers who can support military operations and assist civil authorities. While reservists are not full-time military members, they maintain professional skills and education that enhance their effectiveness. Celebratory customs may include commemorative events and recognition of the service and sacrifices of reservists.