Royal Air Force Greencastle or more simply RAF Greencastle is a former Royal Air Force airfield located 2 miles (3.2 km) south of the fishing village of Kilkeel and took in a large part of Cranfield Bay. It was opened as an RAF bomber Operational Training Unit (OTU) in April 1942 but it was almost immediately transferred to the United States Army Air Forces (USAAF) and renamed AAF Stn 237.