The 4th Ranger Infantry Company (Airborne) was an airborne-trained infantry unit that was part of the United States Army during the Korean War. The 4th Rangers were created as a result of the actions of North Korean Special Forces units such as the KPA's 766th Independent Infantry Regiment that were overrunning Republic of Korea Army (ROK) and United Nations (UN) units. North Korean special units that were trained in the art of unconventional warfare were beating the ROK and UN units that were stationed in South Korea, pushing them back towards the Pusan Perimeter.