The celebration took over the streets of Old City, not far from where the Marine Corps was founded in 1775.
The event featured speeches on the Marine Corps legacy, a cake cutting and more.
It was followed by a birthday block party, featuring live music, food trucks and guest speakers.
Marine Corps 250 celebrations included the opening of a new restaurant named after the place where it all began.
The Tun Tavern opened with speeches from military veterans, bag pipers and historic reenactments.
The original Tun Tavern served as a significant meeting place during the American Revolution, and is known as the birthplace of the Marines.