Carn Brea (Cornish: Karnbre)[1] is a civil parish and hilltop site in Cornwall, England, United Kingdom.

[3] The settlements of Bosleake, Brea, Broad Lane, Carn Arthen, Carn Brea Village, Carnkie, Four Lanes, Grillis, Illogan Highway, Pencoys, Penhallick, Piece, Pool, Tolskithy, Tregajorran, Treskillard, Tuckingmill and West Tolgus are in the parish.

Traces of fourteen platforms on which would have stood Neolithic long houses have been found within its ramparts, along with pottery and flint artefacts.

Edge grinding stones, blanks and incomplete and finished axes found on the site indicate the inhabitants were accomplished stoneworkers and traded their products.

Pottery found on the site appears to have been made from gabbroic clay originating nearly 20 miles (32 km) to the south in the present day parish of St Keverne suggesting a complex economic network in the area.

One hut floor was excavated, and sherds of characteristically Iron Age types, including 'cordoned ware', were found.

[10] The Ravenna Cosmography, of around AD 700, refers to Purocoronavis (almost certainly a corruption of Durocornovium), 'a fort or walled settlement of the Cornovii' (unidentified, but possibly Tintagel or Carn Brea).

[12] It is considered to be a folly built on the huge uncut boulders that make up part of its foundations, giving the impression of the building melting into the land.

[13] An East India trading ship named after Carn Brea Castle was wrecked off the Isle of Wight in 1829 and involved in excise tax fraud.

Basset, a mine owner, gained his titles for erecting earthworks to defend Plymouth from combined French and Spanish fleets in 1779, and suppressing a miners' "food riot" in 1785.

The tunnel is rumoured to extend from the top of the carn into Redruth town, but it is probably an abandoned mine working.