High school ROTC is actually JROTC, which stands for Junior Reserve Officer Training Corps. Each JROTC program is linked to the Army, Air Force, Navy or Marines and is designed to teach students the importance of citizenship and service and instill in them a sense personal responsibility and accomplishment.
While JROTC is based in American high schools, ROTC is a college and university program for training future commissioned military officers. As of 2014, the U.S. Marine Corps and U.S. Coast Guard do not have college ROTC programs. ROTC and JROTC were created as part of the National Defense Act of 1916 and expanded with the 1964 ROTC Vitalization Act.