The site comprises the lighthouse tower with attached keepers' accommodation, and later ancillary buildings including former engine house and secondary sector-light tower.
The facility has an unusual plan, in that it was built against the slope of the rock and the main entrance to the lighthouse is via a spinal corridor bisecting the accommodation block. The design includes well-protected cobbled yards for the castellated dwellings which had symmetrically sited privies with decorated doors, a garden, a stone bridge connecting two islets and a unique stone well-head building which may date from William Trench's early deign. Ancillary buildings associated with the establishment of a fog station, including an engine house, were added to the tower in the later 19th century, and a secondary circular tower adjoins the main tower to the southwest was added in 1903-4 to provide a red sector light.
The former engine house is a standard late 19th century Trinity house pattern, circular with recessed mullioned and transomed windows, with raked back upper lights; moulded cornice and blocking course. It has now been converted to Keepers' accommodation, and the square tower of the fog station adjoins this building to the north. This was probably originally the lobby of the engine house, raised in height on conversion to fog station. The original circular lobby at the head of stairs leading from the main entrance in the former accommodation block has 2-centred arched doorway with Trinity House arms over it in its north elevation.
The lighthouse is a tapering circular tower 22m high, on a tooled plinth, ashlar with tooled cornice defining a second stage. It is painted in broad red and white bands. It has deeply recessed windows in upper stage, in lugged architraves. The solid stone crenellated parapet is corbelled out on moulded bracket. The cast iron lantern is continuously glazed with horizontal grid glazing bars. The central entrance gives access to a grand staircase leading directly to the lighthouse, separating the two keepers' dwellings (now amalgamated as one and linked at basement level). Each of these dwellings has two rooms on each floor, with rear wall fireplaces in rear rooms, corner fireplaces to front. The lighthouse tower has ground and first floor store rooms with stone slab ceilings. There is an open stone stairway beyond these with a plain cast iron rail. There are service rooms in upper stage, with a cast-iron tube (formerly housing weights for clock-work rotary mechanism for light) and the ladder stair to lantern. The optic appears to be circa 1870 and has a cast-iron base, with cylindrical shafts with moulded captials and brackets carrying the 6-sided catadioptric lens which rotates on a bath of mercury
The sector-light tower to southwest is a battered circular stone tower with lattice-glazed cast-iron lantern with cast-iron rail to gridded platform. It is finished with lined-out render. Access is via an improvised landing from the main tower.
More recently, fog signals have been built concentrically around the tower and a helicopter pad has been built in one of the walled gardens
The landing places for supplying the lighthouse were connected by narrow gauge railway. The harbour facilities included unloading hooks suspended from pulleys operating on a wire ropeway (the Blondin system).

Event and Historical Information:
A lighthouse was first established on The Skerries circa 1716, built by William Trench as a personal venture, and with a patent established in 1724. His son-in-law Sutton Morgan took over the light in 1725 (confirmed by parliament in 1730 when he was granted the patent of the light to him and his heirs for ever). Circa 1759 the lighthouse was rebuilt for around £3000 as a slightly tapering limestone tower 6.65m (21ft 10in) in diameter and about 9.5m (28ft) high. It was lit by a coal brazier. In 1778, it was inherited by Morgan Jones, High Sherriff of Cardiganshire, who was raised the height in 1804 by 6.7m (22ft). An iron balcony with enclosing the oil-burning lantern was constructed. The lantern itself was glazed all round with square panes and covered by a cupola. Trinity House acquired the lighthouse in 1844 for the record sum of £440,984, and under its auspices, it was largely rebuilt in 1851 by James Walker, consultant engineer. The light shines at a height of 36m (119ft) above the water and is now automatic controlled from Holyhead.

Sources include:
Cadw Listing Documentation
Eames, A, 1973, Ships and Seamen of Anglesey, pg 321.
Dodd, A H, 1971, The Industrial Revolution in North Wales, pg 123.
Davies,H R, 1924 and 1928, `An Account of the Private Lighthouse of the Skerries', Transactions of the Anglesey Antiquarian Society
Hague, D, 1994, Lighthouses of Wales: Their Architecture and Archaeology, pg49-52
Report of the Select Committee on Lighthouses, Parliamentary Papers, 1845.

Maritme Officer, November 2008.

Visited by T. Driver, RCAHMW, 19th April 2016