It is listed simply as a house of indeterminate date, a classification that places it in a frustrating but not uncommon category of Irish monument: noted, mapped, assigned a record number, and then left largely undescribed.

An Cheathrú Gharbh lies in County Mayo, a county whose landscape of blanket bog, glacial drumlins, and Atlantic-facing coastline has both preserved and obscured enormous amounts of human activity. Houses of indeterminate date in this region can range from post-medieval rural dwellings abandoned during or after the Great Famine of the 1840s to structures considerably older, their precise origins blurred by the absence of dateable artefacts, documentary records, or architectural features that might anchor them to a particular century. The rough terrain suggested by the townland's name would itself have shaped how people built and lived here, with exposed stone, poor drainage, and thin soils all leaving their marks on the form of vernacular buildings throughout the west of Ireland.