Built in 1790, Y Glyn has historical associations with many other country houses in the area. Originally a much larger estate and known as Gorphwysfa, it was owned in the early 19th century by the Bicknells who ran the Penrhyn Arms and George Hotels. It was bought in 1846 by the Chester to Holyhead Railway Company who planned to establish a hotel of unprecedented size. The project was abandoned, having only laid out the gardens, due to lack of funds resulting from the overspend on the Britannia Bridge. The property was sold in 1861, and was later owned by the Vyvian Family of the Port Dinorwic Quarries. It was extended c.1959-1970 and the coachhouses, etc were separated off in early 1970s when the name was changed.

Late Georgian, with the main elevation to the SE. It is three-storey, the front roughcast rendered with a plinth, and with a slate roof with wide panelled and bracket eaves and rendered end chimney stacks. The central bay is splayed out with blind openings to the sides, while the bay to the left is set back with narrow eaves and a hipped roof. The windows are small pane sashes (some horned), 6-pane to second floor, 9-pane to first floor and 12-pane to ground floor. There is a fixed glazed window over the modern porch with classical portico, six-panel door and a fanlight. The modern kitchen extension has a verandah to the left with French windows. There is a later pedimented projection to the ground floor with three windows, the central of which is a 12-pane sash. The lawn tothe rear is bounded by cast iron railings with the land dropping away steeply beyond.

The interior retains considerable contemporary detail. The entrance opens onto an octagonal hall with one Baroque and two broken pedimented doorcases and a panelled dado. The dog leg staircase to the right has panelled newels and barley twist balusters. The Drawing Room has a Tuscan Doric screen with panelled piers to ends and Adamesque detailing below the built in display cabinets. there is also a ceiling rose, gilded cornice bands and Rococo chimneypiece with tapered pilasters and fully modelled festoons. The Dining Room retains ? height panelling and Jacobean overmantel (? formerly a bedhead) with mantlepiece (? formerly bed board) inscribed with various signatures and a panelled and carved fireplace with fleur de lys fireback. There is a fine Victorian closet at rear with blue and white porcelain by Shanks of Barrhead.
(Source; Cadw listing database) S Fielding RCAHMW 26/09/2005