509th

509th refers most prominently to units of the United States military that have carried the designation 509. The best known is the 509th Bombardment Group, later redesignated the 509th Composite Group, of the United States Army Air Forces during World War II. Formed in 1944 at Wendover Field, Utah, the group was created to conduct atomic bombing missions as part of the Manhattan Project. It trained with specially modified B-29 Superfortress bombers, often nicknamed Silverplate, and conducted operations from the Pacific island of Tinian.

In August 1945, the 509th carried out the world's first nuclear weapon missions. Hiroshima was bombed on August 6 with Little Boy, followed by Nagasaki on August 9 with Fat Man. The aircraft Enola Gay dropped the Hiroshima weapon, while Bockscar delivered the Nagasaki bomb. These actions contributed to Japan's surrender and the end of World War II. The 509th’s missions established its place in military history as the first and, to date, only unit to deliver nuclear weapons in combat.

Following the war, the 509th remained a central element of the U.S. Air Force’s strategic bombing capability, undergoing several reorganizations as the aviation services evolved. It became part of postwar organizational structures within the Strategic Air Command and its successors, reflecting broader changes in U.S. military air power.

The designation 509th has also been used by other U.S. military entities, including separate airborne or support units formed at various times. However, the 509th Bombardment/Composite Group remains the most widely recognized and historically noted usage of the term.

---