Substantial stretches of those walls still stand, along with around twenty late medieval houses and the collegiate church of St Nicholas, making this one of the better-preserved concentrations of medieval urban fabric anywhere in Ireland. The town also spilled beyond its own boundaries; a suburb existed at the Claddagh on the western bank of the river, and outside the walls there were three friaries, a hospital, a nunnery, and an infirmary, most of them now gone or fragmentary.

The town's origins lie in the 1230s, when the Anglo-Norman lord Richard de Burgh built a castle on the site of an earlier Gaelic stronghold. That stronghold had been held by the O'Flahertys, and was known as Bun Gaillimhe, meaning the mouth or foot of the Gaillimh river, from which the city takes its name. The formal construction of the town's defensive circuit followed in the 1270s, and in 1396 Galway was confirmed as a royal borough, a legal status that gave it considerable commercial and administrative autonomy. By the seventeenth century the military landscape had shifted again; a ring of artillery fortifications was added around the town, reflecting changes in siege warfare that had made the older medieval walls inadequate on their own against cannon fire.

The collegiate church of St Nicholas, founded in 1320, is the largest medieval parish church still in use in Ireland and offers one of the clearest windows into the town's late medieval prosperity. The surviving house remains, though fragmentary, cluster closely enough together to give a sense of how densely the intramural town was built. The town walls themselves appear in several locations around the modern street plan, sometimes forming the backs of later buildings, sometimes standing free, their scale quietly at odds with the everyday streetscape around them.