Redruth (rəˈdruːθ , Resrudh) is a town and civil parish in Cornwall, England, United Kingdom. The population of Redruth was 14,018 at the 2011 census. In the same year the population of the Camborne-Redruth urban area, which also includes Carn Brea, Illogan and several satellite villages, stood at 55,400 making it the largest conurbation in Cornwall. Redruth lies approximately at the junction of the A393 and A3047 roads, on the route of the old London to Land's End trunk road (now the A30), and is approximately west of Truro, east of St Ives, north east of Penzance and north west of Falmouth. Camborne and Redruth together form the largest urban area in Cornwall and before local government reorganisation were an urban district.
The name Redruth derives from its older Cornish name, Rhyd-ruth. It means Red Ford (literally fordred). The first syllable 'red' means ford. The second 'ruth' means red.
Rhyd is the older form of 'Res', which is a Cornish equivalent to a ford (across a river), a common Celtic word; Old Cornish rid; Welsh rhyd (Old Welsh rit); Old Breton rit or ret, Gaulish ritu-, all from Indo-European *prtus derived word in -tu from the root *per " to cross, to go through "; Proto-Germanic *furdúz (English ford, German Furt); Latin portus, all related to the Celtic word.
Again, it is the -ruth (and not the Red- part of the name) which means the colour red.
Beroul's Roman de Tristan features a location in Cornwall called Crois Rouge in Norman French or 'red cross' in English.
Traditionally in the Penwith Hundred, the town has developed away from the original settlement, which was near where the present Churchtown (around St. Euny's Church) district of Redruth stands today. This location is a steeply wooded valley, with Carn Brea on one side and the now-called Bullers Hill on the other. The presence of shallow lodes of tin and copper lying east to west made it an advantageous site for extracting metals, including, tin, lead and copper. The first settlers stayed by a crossing in the river and started extracting metal ores, and this process turned the colour of the river red.