What branch of the US armed services is the oldest?

The Army is considered the oldest branch of the US armed services, having been established on June 14, 1775. This formation was a crucial step in the American Revolutionary War, marking the beginning of organized military operations in the colonies against British rule.

In contrast, the other branches were established later, with the Navy being formed in 1775 but more formally recognized in 1794, the Marine Corps in 1775 as well but functioning primarily as a naval infantry, and the Air Force being officially established as a separate branch in 1947. The distinction of the Army being the first organized military force highlights its foundational role in the early defense and establishment of the United States. The Army's long history and continual evolution in tactics and technology also contribute significantly to its legacy as the oldest military service in the nation.