United States

The United States government was the first and largest supporter to South Korea during the Korean War.
 
The U.S. Army sent nine divisions: the 24th Infantry Division, the 25th Infantry Division, the 1st Armored Division, the 2nd Infantry Division, the 3rd Infantry Division, the 7th Infantry Division, the 1st Marine Division, the 40th Infantry Division, and the 45th Infantry Division.  Additionally, two battle regiments and numerous supporting units were provided.

From 1950 to 1953, the U.S. deployed 300,000 troops to Korea. In 1952 when the number of the UNC forces reached its height, 50 percent of the ground troops were ROK forces, 40 percent were U.S. forces, and 10 percent were other UNC member nations. U.S. military forces executed extensive operations throughout.

Along with ships from many nations, the U.S. Naval Forces Far East gained and maintained command of the sea from the beginning of the war. The Far East Navy provided naval support from July 1950 to July 1953. The 7th Fleet, 90th and 95th Maneuvering Forces also provided naval support during the same timeframe. Naval support included air strikes, naval gun bombardment, and the transportation of troops and supplies.
 
In conjunction with the allies, U.S. Air Force, Navy, and Marine aviation elements secured air superiority early in the war. These aviation elements also provided much needed close air support to UNC ground forces. The U.S. Far East Air Force provided support from June 1950 to July 1953. The 5th Air Force provided air support from June 1950 to June 1954.
 
The U.S. Air Force, the 5th Air Force, and the Strategic Bombing Command, under command of the Far East Air Force, operated air strikes and executed close air support operations to assist UNC ground troops.
 
During the Korean War 1,789,000 U.S. military personnel served in the Korean theater of operations.
 
The U.S. suffered 137,250 casualties including 36,940 killed in action, 92,134 wounded in action, and 3,737 missing in action.
 
The U.S. has maintained steady support to ROK since the beginning of the Korean War. There are about 28,500 U.S. troops currently stationed at three Army bases and two Air Force bases on the Korean Peninsula. About 19,500 soldiers, 7,800 airmen and women, 350 sailors, and 120 Marines are stationed in South Korea.