Which military branch is the USMC a direct descendant of?

The United States Marine Corps (USMC) is a direct descendant of the British Royal Marines because both share a common lineage and similar operational roles. The Royal Marines were established in the 17th century as a naval force that specialized in amphibious warfare and boarding operations, which was essential for the British Navy. The USMC was formed in 1775, closely modeled after the structure and practices of the Royal Marines to perform similar functions within the emerging U.S. Navy.

The Marine Corps was designed to provide a force capable of conducting shipboard operations and engaging in land-based combat, much like the British Royal Marines. This historical connection marks the Royal Marines as a significant influence on the establishment and evolution of the Marine Corps in America.