Historical version 10 of Oxford Castle (view current version)
Oxford Castle, or mound, was the site of the castle built in 1071 shortly after the Norman conquest. The castle was of a motte and bailey design with the bailey being located where Oxford Prison is now sited. Only the mound of the motte and St George's Tower now remain. Interestingly the city walls predate the castle.
http://www.castleuk.net/castle_lists_midlands/164/images/oxfordcastle2.jpg
OS X co-ord:
451015
OS Y co-ord:
206183
(Latitude:
51.751561
Longitude:
-1.260897)