Blackpill Mill was a water-powered medieval manorial corn mill and features in records of the lordship of Gower from which some details of its early history can be gleaned. The mill dates from before 1319 when its alienation (ownership transfer) from the manor, after 1307, is recorded. It was thus absent from the accounts of 1338 though the same document notes that a miller, Walter Meleward, paid rent of 6d for a weir, or fishtrap, `iuxta Blakepulle?, indicating that the mill was still functioning though outside demesne control.
The mill was returned to the demesne before 1367 when it was farmed for 11 years to William Tyler and John Janot for £3 6s 8d annually. Maintenance costs came to 8d for two twystes (the eyed parts of hinges) and 60 nails. The same accounts also describe the mill's alienation and subsequent recovery: the mill (with other lands) had been granted to John de Horton and his heirs at the annual rent of one red rose for the term of his life (peppercorn rent). After his death, £2 was paid annually (by whom is not stated) until 1357-8 when the mill was `released to the lord?. In 1369, an Inquisition post mortem of the lord of Gower recorded, amongst his possessions, one mill in the manor, that of Blackpill (Blakepolle) valued at £1.
In the accounts of the lordship for 1400, under Oystermouth, is an unnamed watermill, presumably Blackpill, which yielded £1 18s 0d from sales of unspecified grains during eight months of the year. However, £1 0s 5d was spent on extensive repair work: a new waterwheel and cogwheel; iron stays (for the axle), sieves, lubricants and nails purchased. A smith was employed to repair the spindle and to sharpen and steel the millpicks. The mill house roof was repaired and the millpond scoured.
The mill was `in the hands of the lord? for lack of a farmer, a situation shared at this time by other demesne mills now operated directly, while others lay derelict. This all points to difficulties that beset demesne milling in the later fourteenth century as it became increasingly difficult to profit from the industry in the face of high running costs and the impending Glyndwr Revolt.
The mill site is currently occupied by a restaurant. The leat was originally fed by the Brockhole stream until landscaping of the Clyne Castle Estate during the nineteenth century rendered it obsolete, though lengths of channelling can still be seen in Clyne Gardens. A new leat was constructed to the north of the mill tapping water from the Clyne river, and parts of this are still visible.
The miller's house was attached to the mill on its south side (NPRN 18037).

Sources:
D.K.Leighton, 'The demesne watermills of Gower in the fourteenth century: a reappraisal', Melin 21 (2005), 9-36.
B.Taylor, Watermills of the Lordship of Gower (Swansea 2008).

David Leighton, RCAHMW, 19 May 2016