The mapmakers called it Archer's Island, but the older and more revealing name is Anker's Island, a corruption of the word anchorite. An anchorite was a religious recluse who would be literally walled into a small cell, usually adjoining a church, to live out a life of prayer and contemplation in permanent enclosure. That such a figure was associated with this particular sliver of land in the Nore, roughly 215 metres long and only about 50 metres wide, gives the island a strangeness that its unremarkable appearance on a map does little to suggest.

The historian William Carrigan, writing in 1905, drew on local tradition to describe both the anchorite's cell and the remains of a small church that once stood on the island. The church was modest almost to the point of severity: approximately nine metres long and four and a half metres wide, with walls only about sixty centimetres thick. By the time Carrigan was recording it, even those thin walls had been largely destroyed. He placed the blame squarely on a man named Edward McCulloch, who around 1800 dismantled most of the structure and carried the stone off to build Ballyconra mill. The north, south, and east walls were mostly taken; the west wall was removed entirely. What Carrigan found standing amounted to little more than seventy centimetres of masonry. The southern part of the island, he noted, was the more habitable portion, fertile and slightly elevated, while the northern section was boggy ground. The river channel on the southern side has since been filled in and absorbed into reclaimed farmland, so the island's relationship to the water has shifted even since Carrigan's time.