Tan-y-Graig was built in the mid 18th century or earlier. The house is built of rubble stone which is rendered, square chimney stacks to either gable and a single storey extension to the east. The site is marked on the 1st edition OS 25" map, CA XXIII. 7, of 1889.
Source: Caernarvonshire Inventory, Vol I, Ref No. 231.