The Oxford Guide

The city walls originally ran from the castle around the north of the town along the southern edge of Broad Street. The three gates Westgate, Northgate and Eastgate survive only in name through the Westgate shopping centre, St. Michael at the Northgate and Eastgate Hotel; there is also Littlegate Street near St Ebbe's. Turl Street commemorates the 'twirl' gate. St Aldate's is said to derive from the 'old gate' rather than any saint of that name.

The city walls can most clearly be seen in the Turf and New College, as well as on the south edge of Pembroke College.

http://www.spring-grove-gallery.com/gallery/images/City_Wall_New_College.jpg