The Earls of Pembroke walled the town probably from the late thirteenth century, tying the walls into the castle. Most have gone, but a stretch of about 225 metres survives on the south side of town, from Common Road to Rock Terrace, with two bastions, one topped by a restored late eighteenth-century gazebo.
Pick up the town walk leaflet at the tourist information centre on the Commons; it covers the walls, the millpond and the best houses on Main Street in about an hour.