1052 to 1074, then its staffing levels were reduced, until 1220, when it ceased to exist as a monastic house and was abandoned. It was located at , which is in the south of the village in the grounds of College Farm. A Field Investigator's comment from 17 February 1964 states that there is no material evidence of antiquity. Alkborough Priory Cell is included in the English Heritage Archive (Number: SE 82 SE 7, Monument Number: 61223). Wartime Bombing range Alkborough Flats was home to a bombing range during the Second World War. The following is a summary of an oral history provided by an Alkborough resident who was school age during Second World War: The bombing range itself took the form of a chalk marker on Alkborough Flats, and two observation posts positioned on the ridge overlooking the target. An RAF detachment from RAF Elsham Wolds, including two sergeants, were billeted in the southern of the two observation posts. Bombers would take off from Elsham, and drop smoke bombs on the target. Following a bombing run, a bearing on the bomb's landing site was taken from each observation post, and the position of the site calculated using triangulation. During one bombing run, a horse was killed, and another bomb narrowly missed a group of children sledging. After the war, agricultural workers ploughing on the Flats regularly reported releasing smoke. During the establishment of the Alkborough Flats Tidal Defence Scheme in 2005/2006, a large quantity of World War II ordnance was removed from the site under supervision of bomb disposal officers. Currently, very little remains of the southern observation post, though an entire wall of the northern observation post is still standing (including the observation windows). The southern observation post was located at , and the northern at . They are both accessible to the public via a public footpath. The location of the chalk target marker is not known exactly, but was somewhere to the west of the new bird hide, which is located at . Defensive structures A number of Second World War defensive structures were also in the Alkborough area, including: Three searchlight batteries. One of these (Site 3) was located just west of Whitton Road, at . It was staffed by 1 Troop of 323 Searchlight Battery from October 1941. It was established as part of a special deployment of searchlights to defend the Humber Estuary,