Warren was a parish in the
hundred of
Castlemartin, which in pre-
Norman times was part of the
Cantref of Penfro in the
Kingdom of Dyfed. A prominent ridge in the northern part of the parish is crossed by a ridgeway that may be of prehistoric origin. The origin of the name is obscure, but there is a Warren Farm (a
listed building) and an ancient fortification (a scheduled monument) close by. A 1578 map in the British Library shows the parish as
Waren. Merrion Court is a Grade II listed building in the east of the parish, a 19th-century structure built on 18th century ruins.
Richard Fenton, in 1811, described the house as a ruin, previously a manor belonging to
Lord Cawdor. Merrion Court's Granary Range and Mill are also Grade II listed. Another listed building in the parish is an 18th or early 19th cottage (originally two or three) called
Cold Comfort. Since 1801, the population (then 160) has been sparse and scattered in this agricultural landscape, and fell in most subsequent decades, to a low of 86 in 1961. The number of houses in the parish halved between 1831 and 1961. The religious census of 1851 described the parish as "...a small Parish consisting of Three Farms only with a few cottages tenanted by poor Labourers and families who are mostly Dissenters or Independents whose place of Worship is situated in a Neighbouring Parish although they occasionally attend the Church". From 1939 to 1948, the
Castlemartin Training Area was establishedits main base is at Merrionabsorbing most of Warren parish. ==St Mary's Church==