Inishtrahull in Co. Donegal is the northernmost inhabitable point of Ireland. The only part of Ireland that is further north are the Tor rocks, about a kilometre away. The islet of Rockall is much further north still, though its ownership is contested between Ireland and the UK.
Inishtrahull was inhabited until 1929, when it was evacuated. The story goes that illegal fishing by French, Scottish and English boats made it impossible for the remaining people, who relied on fishing for their living, to live there. Only the lighthouse keepers remained.
There has been a light here since 1812, and it was built on the eastern side of the island. In 1905, a fog signal was established on the western end. In 1957, the old tower on the east end was demolished and replaced with the new lighthouse adjacent to the fog station, pictured here.
(You can buy a print of this photograph at: https://buff.ly/2ocC6DA)