Kenmara, 45 North Street, Ballycastle, Co Antrim

Kenmara is a well-maintained late 19th-century villa of special architectural and historic interest, situated dramatically on a cliff-top site overlooking Ballycastle Bay and the North Antrim Coast.

The house was built around 1890 by a London solicitor named Grier. It is a two-storey structure of five bays arranged in a complex plan comprising a two-storey north-west block with a double-pile thrust against its south-west side and various single-storey projections. The walls are roughcast rendered with a plinth and painted white. Natural slate roofs have tall chimneystacks with pronounced caps and tall pots, and the medium eaves overhang shows exposed rafter feet with box PVC guttering.

The south-east entrance front features a one-bay-wide projecting gable with an eight-pane casement window at ground floor and a four-pane casement window above, the head of which rises above the eaves line. The gable is decorated with a kingpost truss with plaster infill panels, and the bottom boom forms the gable overhang. The panelled entrance door with fanlight is positioned in the corner with a six-pane casement window to its left. Above are two unequal dormer windows, one with a one-way pitch roof and the other gabled. At the south-west corner is a short projecting two-bay single-storey wing with four, four and six-pane casement windows. A glazed lean-to canopy supported on slender iron columns spans the space between this projection and the main block. The north-east façade, overlooking Rathlin Sound, is three bays wide with two canted bays and one double-pane casement at first floor level. Each canted bay has continuous glazing at each floor with slate-hung spandrels, and the top windows break the eaves line, with the bays slated hip-fashion. The north-west façade is similar in form and treatment to the entrance front with slight variation in window disposition, and incorporates a fully glazed conservatory extending from the projecting gable. The south-west façade presents a series of gables in recessed pairs expressing the double-pile core of the house. All gables are treated similarly with double-shaped purlins near the end of moulded bargeboards. A gabled double garage stands at the west corner. A high wall with a single door joins the garage to the single-storey wing of the entrance front, forming an enclosed yard. The house enjoys a superb detached setting at the top of North Street where it joins Clare Road, with a 60-metre cliff face at the side of the garden. The well-kept garden practically surrounds the house.

The villa gained special historic significance in 1898 when it became instrumental to Guglielmo Marconi's wireless experiments between Ballycastle and Rathlin Island. Lloyd's of London commissioned Marconi to establish wireless communication across the ten-mile distance between Rathlin and the mainland, at that time the longest signal sent over water. Rathlin was the first landfall for ships leaving America, and a semaphore station operated at Tor Head, but frequent fog had impeded communication. In June 1898, Marconi's assistant George Kemp arrived in Ballycastle and met Lloyd's agent John Byrne. They established a base at the Eastern lighthouse where the Lloyd's hut was located. After initial trials at various sites proved unsuccessful, and after an interlude in Dublin, Kemp returned at the end of July with student engineer Edward Glanville, who set up equipment on Rathlin with instructions to transmit daily. Kemp tried numerous locations in town, including atop the spire of Saints Patrick and Brigid's Church, but found no suitable space for recording transmissions. He then secured a room at Kenmara and used it in conjunction with a jib borrowed from the Coastguard operating a crane in the harbour. This apparatus allowed him to receive signals from the island. Glanville tragically died on 22 August, found at the bottom of a cliff at Ballyconaghan on Rathlin, having fallen while walking along the cliff-top; no foul play was suspected.

On 24 August, Kemp's diary records that he erected a new mast 104 feet to the top of the spirit in a field 104 feet from the window of a child's bedroom which was loaned to him on the north side of the house. On 25 August 1898, Kemp instructed Lloyd's transmitter operator Mr Byrne in Ballycastle, then sailed to Rathlin where he refitted the station and exchanged signals with Ballycastle until 1.00 pm. The experiment was repeated on following days. When Marconi arrived on 29 August, the sensitive tube on Rathlin broke on 30 August, and the decision was taken to halt work from Kenmara as the house owner would be returning. Kemp left Ballycastle on 1 September. The child's bedroom, identified as being located under the eaves above the front door, is now a bathroom. A blue plaque was erected on the house front in 2000 recording this historic event.

The listing extends to the house and gates.