A leacht is a low, roughly rectangular cairn or pile of stones, typically associated with early Christian devotional practice, often used as a station for prayer during a pattern or pilgrimage circuit. The one on Caher Island sits within a landscape already known for its early monastic remains, on an island that drew pilgrims for centuries, yet this particular structure has attracted little documented attention compared to its surroundings.

Caher Island, sometimes written Caher or Cathair, lies in Clew Bay and has long been associated with early Christian activity, likely dating to the early medieval period. The island is part of a broader network of pilgrimage sites along the west Mayo coast, loosely connected to the cult of St Patrick and the wider tradition of Atlantic seaboard monasticism. Leachta of this kind are found at several Irish pilgrimage sites, where they served as focal points for circumambulation, prayer, and the leaving of votive offerings. The specific history of this particular leacht, its date of construction, its precise role within the island's devotional landscape, and its current condition, remain matters where the documentary record is thin.