Carfax is located at the conjunction of St Aldate's (south), Cornmarket Street (north), Queen Street (west) and the High Street (east) in Oxford, England. It is considered to be the centre of the city, and is at . The name "Carfax" derives from the French "carrefour", or "crossroads".
Carfax Tower is located at the north-west corner of Carfax. The Tower is all that remains of the 13th century St Martin's Church and is now owned by the Oxford City Council. It is 23 m (74 ft) tall and still contains a ring of six bells, recast from the original five by Richard Keene of Woodstock in 1676. These chime the quarter hours and are rung on special occasions by the Oxford Society of Change Ringers.
It is possible to climb to the top of the tower for a good view of the Oxford skyline. The tower is open 10am–5.30pm (Easter to October) 10am–3.30pm (October to Easter).
In March and April 2003, Carfax was used as the meeting spot for anti-war protests.