(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 peninsula, terminating with the tiny cathedral city of St David's.
The county's 182 Roman, medieval and post-medieval sites are all included in the third Pembrokeshire list, which covers inscribed stones, stone crosses, holy wells, castles, mottes and baileys, priories, chapels and churches, houses, town walls and a Bishop's palace, along with a wide variety of post-medieval sites from coalmines, kilns and dovecotes through to World War II defensive structures.
The compilation of the list is undertaken by Cadw Welsh Historic Monuments, which is an executive agency of the National Assembly of Wales.
[1] The list of scheduled monuments below is supplied by Cadw[2] with additional material from RCAHMW and Dyfed Archaeological Trust.