CARMARTHEN BAY, a large bay of South Wales; on the coast of Pembroke, Carmarthen and Glamorgan. It opens from the Bristol Channel, between Giltar Point and Worms Head; measures 17 miles, east-south-eastward, across the entrance; makes a somewhat semicircular sweep, with offsets at the Towy and the Burry rivers; and penetrates about 9 miles from the line of entrance to the Towy's month. Caldy Island lies at the west side of the entrance; the Cefn-Sidan sandbank spreads over the north-eastern portion; and the ports of Tenby, Saundersfoot, Carmarthen, and Llanelly are on the minor baylets or rivers. Caldy island forms a natural breakwater; and lights are there and elsewhere to guide the navigation. A very productive fishery might be carried on, but has been strangely neglected.

(John Marius Wilson, Imperial Gazetteer of England and Wales (1870-72))