Lewknor is a village and civil parish in the South Oxfordshire District of Oxfordshire, England about 5 miles (8 km) south of Thame. The civil parish includes Postcombe, and South Weston which was abolished as a separate civil parish and absorbed into Lewknor in 1932. The 2011 UK census recorded the parish's population as 663.
For more information, see the EN Wikipedia article Lewknor.
A Vision of Britain through Time provides the following description of Postcombe from John Marius Wilson's Imperial Gazetteer of England and Wales of 1870-72:
Postcombe has always been referred to as a hamlet in Lewknor parish, but the population given for it in 1871 is substantial as hamlets go. It is marked separately on the map of Southeast Oxfordshire listed below (the white area adjacent to Lewknor), yet there is no evidence of it ever being more than a hamlet within Lewknor. On a road map it is on the opposite side of the M40 motorway to Lewknor and is much further away from the parish village than is South Weston.