The Devon and Dartmoor HER contains over 70,000 records of archaeological monuments (for example, prehistoric flint finds, hillforts and field systems, Roman roads, medieval fortifications, significant historic placenames, sites of palaeoenvironmental importance, Second World War defensive sites, etc.) as well as records of historic buildings, historic landscapes and archaeological events (excavations, archaeological assessments, geophysical surveys, etc.).

The Historic Environment Record was established in 1975 as the Devon Sites and Monuments Register by the Devon Committee for Rescue Archaeology, and in 1979 Devon County Council assumed responsibility for its maintenance. It is now based at both Devon County Council and Dartmoor National Park Authority, where records are supplemented by a collection of unpublished fieldwork reports, photographs, archaeological reports, historic landscape information, unpublished notes and other records.

The Devon and Dartmoor HER records information from the Palaeolithic (250,000 years ago) through to records of Cold War defensive sites from the 20th Century.

It has records for the historic county of Devon including Dartmoor National Park, excluding Exmoor National Park and the unitary authorities of Plymouth and Torbay. These authorities hold their own HERs. Exeter City Council (for the central part of Exeter City) holds HER information in the Exeter Urban Archaeological Database.

The HER has information taken from relevant material in published archaeological and historic sources, as well as acting as a repository for otherwise unpublished sources. Information has been collected from both primary and secondary sources: original documents, historic maps, learned society journals, antiquarian observations and excavations, aerial photographs and modern archaeological fieldwork.