The estate workshops of Glynllifon mansion were probably built by the 2nd Lord Newborough (and therefore before 1832), and provided the ancillary estate services such as gas works, tannery, smithy, slate mill, cartsheds and a timber mill.

The yard is formed by two parallel ranges running north-south linked at either end by screen walls, that on the south with a tall arched entrance. Set to the left is a further range running east-west and midway across the rear of the west courtyard range is an engine house with chimney. Originally there was a barn in the centre of the yard, now only two rectangular features which are possibly the remains of horse gins. All ranges are built of coursed rubble stone with dressed slate lintels and brick voussoirs. They have slate roofs, brick chimneys, and brick dressings. The tall arched entrance has double timber gates and is set within a gable topped by a gabled bellcote with bell in situ, cast by the founders Mears of London. The arch is flanked by broad gabled buttresses which are a diagnostic feature of the 2nd Lord Newborough's work.

The outer side of the east courtyard range borders the road and has mostly replaced glazing in largely original openings. The central two storey block has wide eaves and metal brace plates and there is a blocked carriage opening. The east side comprises a series of stepped ranges of one or two storey height. A two-storey central block has an infilled carriage arch with an external staircase to the first floor and a central gabled lourve; there is a further blocked carriage arch in the south range.

The west range comprises the estate office at the south end, with an adjacent loading bay and then a range of cartsheds below a well lit loft. A slate lintel at the office is marked '16' and there is a first floor plaque inscribed in Welsh to the memory of William Cadwallader Williams. To the right of this are steps up within the covered loading area, then a row of six cartsheds. Those to either end are now infilled that in the north having a Gothick detailed window and door under a single pointed arch. There is also a short south range.

The workshops are now mostly converted to craft workshops.

Associated with: Glynllifon mansion (NPRN 26526) and grounds (NPRN 86377).

(Based on CADW listing description, S Fielding RCAHMW 16/05/2005)