Blackrock Island, County Mayo
| Geography | |
|---|---|
| Location | Off coast of County Mayo, Ireland |
| Coordinates | 54°04′01″N 10°19′14″W / 54.0669°N 10.3205°W |
| Length | 0.4 km (0.25 mi) |
| Width | 0.25 km (0.155 mi) |
| Highest point | 82 metres (269 ft) (approximate) |
| Administration | |
IRL | |
| Demographics | |
| Population | Uninhabited |
| Black Rock lighthouse | |
| Constructed | 1864 |
| Construction | local stone from island |
| Automated | 1974 |
| Height | 15 m (49 ft) |
| Shape | cylinder |
| Markings | white |
| Operator | Commissioners of Irish Lights |
| First lit | 1864 |
| Focal height | 86 m (282 ft) |
| Range | 19 nmi (35 km; 22 mi) (white), 14 nmi (26 km; 16 mi) (red) |
| Characteristic | Fl WR 12s |
Blackrock Island (54°4′0.67″N 10°19′12.66″W / 54.0668528°N 10.3201833°W; Irish: An Tor) is a rocky island rising to a height of 70 metres above sea level and located northwest of Achill Island approximately 12 miles west of Blacksod Bay. Typical rainfall is 72 inches per annum, and the island is often shrouded in mist. It is visible from near the Glosh Tower on the Mullet Peninsula, and, with reference to the other islands in the area, is sometimes described as the "one that looks like a volcano".
There is a small rocky islet 125 m to the east with a length of 80 m. There are about five rocky islets including Fish Rock, Carrickaduff and Carrackabrown spread 1 km to 2 km in a generally westwards direction.