Battle of Osan (1950. 7. 5)
When the South Korean Force was using delay tactics in the early stage of the war after the Han River defense line collapsed, this was the defensive battle in which Task Force Smith of the 1st Battalion of the 21st Regiment of the U.S. 24th Division deployed to Korea first fought against 2 regiments of the North Korea Army 4th Division that was strengthened with 1 tank regiment heading southward at the Jukmi Pass region located in the north of Osan.
Task Force Smith, in cooperation with infantry and artillery, fought fiercely against the North Korean infantry and tank unit for 6 hours in this battle, but they were forced to retreat to Cheonan via Anseong due to the enemy's strong tank unit. This battle was recorded as the first battle that U.S. ground troops fought during the Korean War.
Battle of Daejeon (1950. 7. 18~20)
This is the defensive battle in which the U.S. 24th Division had been using delay tactics along the Seoul - Busan axis since the Osan battle fought against 2 North Korean divisions (the 3rd and 4th Division). As the U.S. 24th Division was immediately deployed from Japan, it lacked in understanding the geographical condition and shape of the Korean peninsula and the status of the North Korean Army when it began this battle. While fierce battles continued under such a difficult condition, the U.S. 24th Division was attacked from all directions with the southward roads from Daejeon cut off. The U.S. soldiers fought bravely, including the Division commander Major General Dean himself launching 3.5 inch rocket artillery at an enemy tank. Despite of a retreat order from above, Major General Dean tried to defend Daejeon along with his troops up to the very end. As Daejeon was captured by the enemy and the U.S. 24th Division fell apart, he failed to retreat and was captured by the enemy. The U.S. Forces were able to destroy a North Korean tank (T-34) using a 3.5 inch rocket artillery in this battle for the first time since the beginning of the war. The North Korean Army's infantry unit did not suffer heavy loss but the artillery and the armor unit suffered a significant amount of casualties.
Battle of Youngsan (1950. 8. 6~19, also known as the Nakdong River Perimeter Battle)
This was the battle in which the U.S. 24th Division dispatched in the Nakdong Riverdefense line, west of Changnyeong and Youngsan, fought against the North Korean 4th Division. The 24th Division was dispatched to the Nakdong River defense line operation with very little time to regroup themselves from the loss in the Daejeon Battle. As the North Korean 24th Division surprisingly crossed the Nakdong River from the Hapcheon direction and advanced to Youngsan after passing the 24th Division's defense line, U.N. Forces were facing a crucial moment at the Nakdong River defense line. Therefore, the U.S. 8th Army Corps dispatched their reserve units, 9th Regiment of the 2nd Division of the U.S. Reserve Force, the 27th Regiment of the 25th Division and the Marine 1st Brigade in succession to the region and defeated the North Korean Army to the west of the Nakdong River. The extent of the loss from this battle was not exactly known, but the North Korean 4th Division suffered heavily and it never returned to the Nakdong River battle line again.
Incheon Landing Operation (1950. 9. 15)
This was the only joint operation between the South Korean Force and U.N. Forces during the Korean War. When the North Korean Army advanced to the Nakdong River battle line, this operation was the wide siege operation launched to completely cut off North Korea's rear side by advancing to Seoul after the U.S. 10th Army Corps (the U.S. Marine 1st Division, the South Korea Marine 1st Regiment and the South Korea Army 17th Regiment) landed in Incheon.
U.N. Armed Forces that had been using delay tactics for 3 months since the start of the war planned an attack on the North Korean Army's rear side while retreating.
The operation was launched on Sep. 15, 1950, when the North Korean Army was no longer able to sustain its offensive at the Nakdong River battle line.
As the U.S. 10th Army Corps succeeded in this surprise attack, landed troops secured the bridgehead in the Incheon area the next day after the attack and advanced to Seoul to regain control of Seoul on Sep. 27. As the counteroffensive at the Nakdong River launched along with this operation became successful, allied troops were able to join in the Osan area and the North Korean Army invading the South became helpless. This was the one operation that made the South Korean Force and the U.N. Armed Forces, who had been on the defensive end from the start of the war, become offensive.
Pyongyang Recapturing Operation (1950. 10. 9~19)
This wasthe operation that recaptured Pyongyang by the U.S. 1st Army Corps (the U.S. 1st Cavalry Division, the U.S. 24th Division, the South Korea 1st Division and U.K. 27th Brigade) on Oct. 19 after passing through the 38th parallel line near the Gaesung - Goryangpo area following the U.N.'s northward advance operation and defeating the North Korea's 38th Parallel Line Defense Force and Pyongyang the Defense Force.
After passing the 38th parallel line, the U.S. 10th Army Corps marched to Pyongyang by way of Sariwon - Hwangju, Sibyun-ri - Suan and along the way fought locally against the North Korean Army at Geumcheo, Sariwon, Heukgyo-ri, Sibyun-ri, Yul-ri and Daedong-ri. Pyongyang was finally regained after the South Korea 1st Division captured the North Korea administration building and the U.S. 1st Cavalry Division attacked the Pyongyang station area.
Battle of Kunwu-ri (1950. 11. 26~12. 1)
This was the battle in which the U.S. 2nd Division fought against the Chinese Communist Army near the Kunwu-ri area while advancing northward to secure the path of retreat for the main unit of the U.S. 8th Army Corps. While launching an attack from the Kunwu-ri to Onjeong-ri direction following the U.N. Forces' full scale Offensive Operation (Christmas Operation), the U.S. 2nd Division faced the Chinese Communist Army's 2nd big offensive. As the Chinese Communist Army dispatched their main force to Kunwu-ri, an important traffic point on the Cheongcheon River, the U.S. 2nd Division took over Kunwu-ri and carried out the fierce defensive battle there for 2 days. As a result of this battle, the U.S. 8th Army Corps were able to earn the time for a safe retreat but some of the Chinese Communist Army infiltrated to south and blocked the narrow road connecting Kunwu-ri - Gaecheon to be used as a retreat path for the 2nd Division. The 2nd U.S. Division therefore, had to suffer heavy casualties to pass through it and the area was later called "Valley of Whip" by the U.S. Army.
Battle of Lake Jangjin (1950. 11. 27~12. 11)
This was the battle which the U.S. Marine 1st Division carried out near the Jangjin Lake to escape after being surrounded by the Chinese Communist Army. When the U.S. 8th Army Corps were engaging in a fierce fight against the Communist China 13th Army Corps in the western battle line, the U.S. Marine 1st Division under the U.S.10th Army Corps command in the eastern battle line were advancing to the north of the Jangjin Lake to join the units in the western battle line as it was attacked by the Chinese Communist 9th Army Corps.
While escaping over 40km of the canyon area from Yudam-ri to Jinheung-ri tightly surrounded by the Chinese Communist Army with around7 divisions, the U.S. 1st Marine Division suffered heavy casualties under the extreme cold weather for over a 2-week period, but they were able to retreat to Hamheung by launching a bold breakthrough operation with close-range air support from the U.N. Air Force.
As this battle delayed the Chinese Communist Army's advance by 2 weeks, the South Korea Force and U.N. Forces that had advanced to the northeast region earned the time to assemble in Heungnam, and Heungnam Retreat Operation immediately followed became possible. Especially, as the Chinese Communist 9th Army Corps were not able to take part in the Chinese Communist Army's 3rd offensive, which made U.N. Forces seriously consider their withdrawal from the Korean peninsula due to the heavy loss occurred in this offensive, the Chinese Communist Army's third offensive had to stop near the Suwon area without going further due to the lack of following support troops. On the other hand, the South Korean Force and the U.S. Force seized a chance for a counteroffensive and were able to lead the war from that time on.
Battle of Jipyeong-ri (30km Northwest of Wonju; 1951. 2. 13~16)
This was the battle in which the 23rd Regiment of the U.S. 2nd Division, along with a French battalion joining them, defended the intensive attack by 3 divisions under the command of the Chinese Communist 39th Army Corps at Jipyeong-ri, north of Wonju during the Chinese Communist Army's 1951 February Offensive (the 4th Offensive). Because the adjacent units in both left and right side retreated due to the Chinese Communist Army's attack, the U.S. 23rd Regiment and the French Battalion were surrounded by the Chinese Communist 39th Army Corps in all directions, but they were able to defend Chinese Communist series of attacks for 4 days under isolation to accomplish the order of defending Jipyeong-ri. The battle line was later reconnected by the U.S. 5th Cavalry Regiment's reaching the area breaking through the surrounding Chinese Communist from the rear and this battle played a key role in stopping the Chinese Communist February Offensive. The Chinese Communist suffered heavily in this battle and their February Offensive failed. U.N. Forces were able to change the direction of the war for the first time since the Chinese Communist intervention and created an opportunity for a counteroffensive. Also, this was the first time that the Chinese Communist human wave tactics failed. Therefore, U.N. Forces gained confidence against the Chinese Communist Force and were able to launch a counteroffensive to later recapture the 38th parallel line.
Battle of Bunker Hill (North of Hongcheon, 1951. 5. 16~19)
This was the battle in which "K" Company of the 38th Regiment of the U.S. 2nd Division fought against the Chinese Communist Army's attack at Hill 800, north of Hongcheon, during the Chinese Communist 2nd Spring Offensive launched in May of 1951. The Chinese Communist Army carried out close-range combat human wave tactics every night to capture this hill but this Company resisted using strong defense facilities built in advance. When the hill was captured by the Chinese Communist Army, they regained it using close-range shooting in the position and counterattack. As a result of this battle, the Chinese Communist Army created a big new path to advance ranging from Hyun-ri to Hajinbu-ri but U.N. Forces were able to keep Hongcheon and stop the Chinese Communist Army's advance there because of "K" Company's defense of Hill 800.
Battle of Old Baldy (Northwest of Yeoncheon ;1952. 6. 6~29)
This was a representative battle sustained for taking over a hill while the cease-fire talks were held. The U.S. 45th Division facing the Chinese Communist Army with their main resistance line set at the south of Yeokgokcheon located in the front of Daegwang-ri captured Hill 266 located in the middle of two sides in a surprise attack to improve their defense line, and they established a platoon size strong outpost. However, the Communist Chinese Army launched a counterattack against this outpost and the battle for taking over this hill continued. Both sides suffered heavy casualties in this offensive and defensive battle. The top of this hill was peeled off like a bald head during this battle because of repeated artillery and bomb attacks, and this hill was later called as Old Baldy Hill. The battle to take over the hill continued by units responsible for this area, but the hill fell into the enemy's hand in the end.
After the cease-fire agreement, the U.S. Naval and Air force were relocated immediately. Ground troops began withdrawing starting Jan. 1954 and 7 divisions were withdrawnby the next March, but the remaining units continued to perform their duty.