[1] Its core area comprised Carmarthenshire, Ceredigion and Pembrokeshire (the old county of Dyfed) in south-west Wales.

The Trust provides archaeological and related advice to central government, local planning authorities and other public and private organisations.

The Welsh Archaeological Trusts were pioneers in developing Historic Environment Records (HERs) in the 1970s: Wales was the first part of the UK to develop a fully national system of what were then called ‘Sites and Monuments Records’; this fully computerised system was pioneered by the Dyfed Archaeological Trust Chief Executive, Don Benson.

[2] Data included in the Historic Environment Record are publicly available on a dedicated website, Archwilio.

The Trust also undertakes a wide range of field- and office-based projects, is a limited company and a registered charity.