Trefynor-Isaf farmstead has a 'U' shape plan of 18th/19th century, detached buildings, constructed of stone and clay walling. These include a scarfed-cruck, thatched, clay-built, former crog-loft house with later in-line cow-house, and a stable/barn range opposite. A new, c.1840, stone-built house, overlooks the yard.

Said to have been part of the Llanlyr estate, 2 earlier ranges shown on map of 1801.

Visited, Geoff Ward, GA Ward,06/11/2001