Defense Primer: Organization of U.S. Ground Forces

"The Army is the U.S. military’s primary ground force. Title 10, Subtitle B, Part I, Chapter 307 of the U.S. Code addresses the organization of the Army. The Marine Corps serves as the Navy’s land-based fighting force. Title 10, Subtitle C, Part I, Chapter 507, Section 5063 addresses Marine Corps composition and functions. For the National Guard and Reserves, see CRS In Focus IF10540, Defense Primer: Reserve Components..:
U.S. ground troops