The United States Marine Corps (USMC) is a branch of the United States Armed Forces responsible for providing power projection from the sea, using the mobility of the United States Navy to rapidly deliver combined-arms task forces. It is one of seven uniformed services of the United States. Created in 1775, the Marine Corps has been a component of the United States Department of the Navy since 1834, often working closely with naval forces for training, transportation, and logistics.
Captain Samuel Nicholas formed two battalions of Continental Marines on 10 November 1775, in Philadelphia as naval infantry. Since then, the mission of the Marine Corps has evolved with changing military doctrine and American foreign policy. The Marine Corps has served in every American armed conflict and attained prominence in the 20th century when its theories and practices of amphibious warfare proved prescient and ultimately formed the cornerstone of the Pacific campaign of World War II. By the mid-20th century, the Marine Corps had become the dominant theorist and practitioner of amphibious warfare. Its ability to rapidly respond on short notice to expeditionary crises gives it a strong role in the implementation and execution of American foreign policy.
In 2010, the United States Marine Corps had just under 203,000 active duty members and just under 40,000 reserve Marines. It is the smallest of the United States Armed Forces in the U.S. Department of Defense. However, the Marine Corps is larger than the armed forces of many significant military powers; for example, the USMC is larger than the active duty Israel Defense Forces.