In 1334 Edward lll gave permission for a castle, which was demolished in the 19th century. It was the fortification of an existing house, had seven towers, and seems to have been abandoned in the 18th century. It is said that from this time on its stones were gradually incorporated into village dwellings.

An interesting building is Ruan Reading Room, something which features in other Cornish villages. Books and newspapers used to be beyond the pockets of most residents, and a local benefactor would have paid for its construction. Today it is used as a village hall. There is also a church and the Kings Head pub.

Providing a link to the neighbouring parish of St Michael Penkivel is the Grade 11 listed Sett Bridge over the River Fal. This was built c1850 after the Fal became unusable for river traffic to Tregony upstream because of silt from china clay extraction. There was so much being washed downstream that it became feasible to dredge the river for material to manufacture bricks at Trelonk about a mile south of the village. However, the operation was short-lived and only operated from 1891 to 1907. Its tall kiln chimney survives at the junction of Tuckingmill Creek and the Fal.

There are two other settlements in the parish. They are Ruan High Lanes on the main road through the Roseland, and Treworga only a half mile away yet well off the beaten track. At Ruan High Lanes is the Hundred House where a district (or hundred) court was formerly held to settle local law cases.