The walled borough, immediately south-west of the castle, is part of the modern Kidwelly Town (NPRN 33064). The small borough, measuring some 1.5ha, was established in the south-west section of the D shaped ringwork dilineating the outer enclosure of Kidwelly Castle (NPRN 95633). The castle gardens (NPRN 79038) occupied its north-east section, which, with the castle itself, is a Scheduled Ancient Monument.

The earliest murage grant (royal permission to raise money for the borough walls) dates to 1280 and this may refer to the present remains, which overlie an earlier rampart (see NPRN 303916). By the early sixteenth century the walled borough was said to be deserted, although Water Street to the north was built up and the area around St Mary's Priory (NPRN 301847), south of the river, was flourishing. The borough had three gatehouses, with its main gatehouse (NPRN 303916) situated some 70m from Kidwelly Bridge (NPRN 43101). The bridge would have facilitated passage from the Benedictine Priory, St Mary's Church (NPRN 301847), over the Gwendraeth Fach to the contemporary borough and castle.

Sources include:
James, Carmarthenshire Antiquary 16 (1980), pg 6-15

RCAHMW, 15 March 2013