Lower Upnor and Upper Upnor are two small villages in Medway, Kent, England. They are in the parish of Frindsbury Extra on the western bank of the River Medway. Today the two villages are mainly residential and a centre for small craft moored on the River Medway, but Upnor Castle is a preserved monument, part of the coastal and riverine defences from t…Lower Upnor and Upper Upnor are two small villages in Medway, Kent, England. They are in the parish of Frindsbury Extra on the western bank of the River Medway. Today the two villages are mainly residential and a centre for small craft moored on the River Medway, but Upnor Castle is a preserved monument, part of the coastal and riverine defences from the sixteenth century.