Aberarth mill is located on the east bank of the Afon Arth. It was situated originally on land owned by Strata Florida Abbey, first granted in the late twelfth century, in what became the coastal grange of Morfa Mawr. The earliest known documentary reference is a lease from the Abbey dated 1503. This long-term lease (99 years) with a reference to the previous tenant, suggests that the mill probably dates from at least the early fifteenth century. Earlier records have not survived. Its next appearance, in early eighteenth century records, indicates that it had become incorporated in the Noyadd Estate (NPRN 5838) before 1702. The mill was completely rebuilt in 1819 and is essentially the building that stands today. At the end of the nineteenth century the mill was extensively altered with a saw-mill extension on its south side (powered by the same water-wheel), and the mill building raised with a new roof covering the entire structure. A stable block with a new building housing a corn-drying kiln were added to the mill complex. A new pentrough (carrying water to the wheel) was added subsequently, an arrangement still visible today. The mill went out of use soon after 1930, possibly after a catastrophic accident.
The mill leat is still visible, as a drain, and can be followed from a weir upstream, at SN48206345, for a distance of some 400m whereafter it is obscured by more recent developments. Originally it continued beyond the wheel across common land to enter the river at its mouth. The mill lay disused until 1988 when it was refurbished into a small industrial workshop retaining its corn mill section with its surviving machinery and equipment. The mill building itself is now represented by an L-shaped structure complete with overshot wheel, a lay-out probably little changed from monastic times.
(Historical details from: P.Davis, `Aber-arth Mill and its owners?, Cerdigion 11 (1992), 357-70).

David Leighton, RCAHMW, 2 April 2012