Carmerthenshire is a maritime county in Wales, the largest in the principality. It is bounded on the north by Cardiganshire, on the east by Breconshire, on the southeast by Glamorganshire, on the south by Carmarthen Bay, and on the west by Pembrokeshire. The area is 919 square miles.
The surface of the shire is generally hilly, intersected by narrow valleys, the principal level tract being the Vale of Towy, which extends inland 30 miles. Along the Towy, Cothi, Teifi, and Gwendraeth rivers, the soil is rich and productive.
The chief towns are Carmarthen, the county town, Llanelly, the chief port, Kidwelly, and Talley. Near Llandilo in 1227, Edward I fought one of the last battles that destroyed Welsh independence. Along the coast are many caves, known to have concealed many famous early-day pirates.