It was divided into two commotes: Cwmwd Penfro in the southwest and Cwmwd Coedrath in the northeast, as shown in the map. The eastern part of Cwmwd Penfro was sometimes called Cwmwd Maenorbier, and the northern part of Cwmwd Coedrath was sometimes called Cwmwd Arberth, but both these were post-Norman lordships, and were probably not genuine commotes. Its civil headquarters were at Pembroke: Rhoscrowther or Penally might have been its ecclesiastical centre.
The cantref was made part of the Norman March in the 12th century, and many castles were built, including those of Carew, Manorbier, Narberth, Pembroke and Tenby. The area became English-speaking, as it continues today, except in the northern part of Narberth parish.