Achillbeg's depopulation followed the slow arc familiar from many small Irish islands - school closures, the impracticality of ferrying supplies and children, the pull of the mainland economy. The inhabitants were eventually resettled on Achill itself or on the mainland nearby. The island sits inside a Gaeltacht, an officially designated Irish-speaking area, and the language tradition was carried over to the new homes the islanders moved into. What remains on Achillbeg now is grass, stone walls, the foundations of cottages, and the rhythm of the lighthouse beam at night.

When the Clare Island Lighthouse was decommissioned on 29 September 1965 after more than a century and a half of service, the Commissioners of Irish Lights needed a replacement to cover the same stretch of approach. They built it on Achillbeg's southern tip and brought it into service the same year. From the air it appears as a small white tower at the very edge of the island, slightly offset from the abandoned cottages further north - a strange geometry of arrival and departure on the same piece of ground.

In 2012, a small plaque went up on Achillbeg marking a hundred years since the boxer Johnny Kilbane won his first world featherweight championship. Kilbane was born in Cleveland, Ohio in 1889, but his father came from this area, and the family connection has been kept alive in island memory. Kilbane held the featherweight title from 1912 to 1923 - eleven years, one of the longest championship reigns in boxing history. The plaque sits in a quiet that has no equivalent in Cleveland: no traffic, no crowds, just a small island honouring a son of an emigrant family who became a champion in another world.

Achillbeg has produced an unusual amount of writing for a depopulated island. In 2005, Jonathan Beaumont published Achillbeg - The Life of an Island, a careful account of the place and its people across the generations. The Irish artist Pete Hogan, who spent time living on the island in 1983, published The Artist on the Island: An Achill Journal in 2013, his own record of months alone with the wind, the sea, and a sketchbook. Both books are the kind that an empty island sometimes produces - written by people who came because there was no one else there, and who left wanting to remember exactly what that had been like.

From the lifeboat station at Kildavnet on Achill, Achillbeg is a short hop across calm water and a much longer hop in any kind of weather. The currents through the sound can run hard. Sheep still graze on the island; visitors who come over with the small boats run from Achill Sound find a place that feels much further from the modern world than the actual distance suggests. Clare Island lies a few miles south across open water, Inishturk further south-west, and beyond them the Atlantic continues until it doesn't.