Pembrokeshire is the fifth-largest county in Wales, but has more scheduled monuments (526) than any except Powys. This gives it an extremely high density of monuments, with 33.4 per 100 km². (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. 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.

Over two-thirds of Pembrokeshire's scheduled monuments (346) date to pre-historic times. Even this is too many entries to conveniently show in one list, so the list is subdivided into three, separating the Roman to modern on one list, and subdividing the prehistoric sites along the lines of the former local districts of Preseli Pembrokeshire, (the northern half) and South Pembrokeshire. The list below shows the 233 sites in the north. This includes hill forts, promontory forts on both coastal headlands and inland locations. It also includes a variety of enclosures, hut sites and Raths, a wide range of burial sites and other ritual and religious sites listed as barrows and chambered tombs, stone circles and standing stones. There is a matching list of 113 prehistoric sites in south Pembrokeshire.

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.

Scheduled monuments have statutory protection. 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.