The Oxfordshire Ironstone Railway (the O.I.R.) was a standard gauge railway that served an ironstone quarry near the village of Wroxton in Oxfordshire. It linked to the Great Western Railway about to the east, just north of the town of Banbury. Both the quarry and line opened in 1917 and closed in 1967, when the Ironstone ran out. It never became part of British Rail and was run by the quarry's owners.