The River Og is a short river in Wiltshire.
The river flows through a gap in the Marlborough Downs which creates a natural transport route, now followed by the A346 road and once used by the Midland and South Western Junction Railway.
The name is a back-formation from Ogbourne (which itself means Occa's stream).
- Glover, J.E.B., Mawer, A. and Stenton, F.M. (1939) Place-names of Wiltshire, p.9