Newport Arch probably got its name in the medieval period, as the gate leading to the suburb of Newport, but its importance is as the Roman north gate of the Upper City/colonia through which passed Ermine Street that linked London to York. The first gate here was undoubtedly the 1st-century timber gate of the legionary fortress, but no trace has yet been found. If it was similar to the East Gate, a stone facing was added to it in the early 2nd century.
Newport Arch is part of the new colonia gateway that was constructed c.AD200. What we can see today are the inner arch, an eastern footway arch and part of the springer of the western footway arch, whose collapsed remains were revealed when the house on the west side was demolished and rebuilt in 1824. The outer northern arch was demolished c.1790.
The roadway was c.1m higher in the late 18th century as evidenced by a contemporary drawing, and the footway arch was blocked in with a window inserted. The footway was reopened c.1826.
The bastion, the semi-circular front of the western gate tower, is visible to the north-west of the arch, having been excavated in 1954. There would have been a corresponding bastion on the east side, now underneath 52 Bailgate.
There were re-buildings in the medieval – possibly as early as the late 11th century - and post-medieval periods. The lengths of wall on the north and east sides of the arch are medieval in date. It was a favourite subject for landscape artists in the 18th and 19th centuries. The arch has since been subject to damage from motorised vehicles, particularly to the upper part hit by a lorry in July 1964, which necessitated its dismantling and rebuilding.