Scheduled Monuments in Pembrokeshire Scheduled Monuments in Pembrokeshire Pembrokeshire is the fifth-largest county in Wales, but has more Ancient Monuments (526) than any except Powys. This gives it an extremely high density of monuments, with 33.4 per 100km2. (Only the tiny County Boroughs of Newport and Merthyr Tydfil have a higher density). With three-quarters of its boundary being coastline, Pembrokeshire occupies the western end of the West Wales peninsular, terminating with the tiny cathedral city of St David's. It was a historic county in its own right but between 1975 and 1996 it joined Carmarthen and Ceredigion in the much larger county of Dyfed.
Pembrokeshire landscape was subject to considerable change as a result of ice ages; about 20,000 years ago the area was scraped clean of soil and vegetation by the ice sheet; subsequently, meltwater deepened the existing river valleys. While Pembrokeshire is not usually a seismically active area, in August 1892 there was a series of pronounced activities (maximum intensity: 7) over a six-day period. The Pembrokeshire coastline includes numerous bays and sandy beaches. The Pembrokeshire Coast National Park, the only park in the UK established primarily because of its coastline, occupies more than a third of the county. The park contains the