Onley is a deserted medieval village in Northamptonshire, England, forming a small salient along the border with Warwickshire. Onley lies within the parish of Barby. The site is bordered on the north by the M45 motorway. On the east are HMP Onley and Rye Hill, which make up most of Onley's modern population, and on the south-west is the A45 road. The Oxford Canal and the disused trackbed of the Great Central Railway run close to the eastern boundary.