In simple terms, the U.S. Armed Forces are made up of the six military branches: Air Force, Army, Coast Guard, Marine Corps, Navy and, most recently, Space Force.

The Department of the Air Force was created with the signing of the National Security Act of 1947. The Air Force’s missions are broken down into Air and Space Superiority, Global Attack, Rapid Global Mobility, Precision Engagement, Information Superiority and Agile Combat Support.

The Department of the Army was created on June 3, 1784 by the Congress of the Confederation at the end of the Revolutionary War. "To fight and win America's wars," the Army exists to organize, equip, and train forces “for the conduct of prompt and sustained combat operations on land.”

The United States Coast Guard was established on Aug. 4, 1790.  The Coast Guard is charged with maritime security, safety, and stewardship. While the Coast Guard operates under the Department of Homeland Security during peacetime, during times of war, it can be transferred to the Department of the Navy, as it did in WWI and WWII.

The United States Marine Corps was created on November 10, 1775.  It is a combined-arms task force known for its focus on aggressiveness and the offensive. The Marines have been central in developing groundbreaking tactics for maneuver warfare; they can be credited with the development of helicopter insertion doctrine and modern amphibious assault. 

The Department of the Navy was founded on October 13, 1775, with the Department of the Navy established in 1798. The Navy's mission is to “maintain, train and equip combat-ready naval forces capable of winning wars, deterring aggression and maintaining freedom of the seas," and it does so with warfare specialities that include aviation, surface warfare, nuclear submarines, special forces and support services. 

The United States Space Force was signed into law Dec. 20, 2019 as part of the 2020 National Defense Authorization Act. SpaceForce.mil went live shortly thereafter.