On September 20, 1945, the U.S. Military Government Office was established in Seoul to take charge of security and administration in areas south of the 3.8-line.

The first commander was Lt. Gen. J. R. Hodge, commander of the 24th U.S. Army.

The U.S. military government transferred administrative power to the South Korean government established on August 15, 1948, after implemented legislative and administrative functions.