The name itself is suggestive: townland names incorporating "Earl" often point to lands once held by, or associated with, powerful Anglo-Norman or Old English noble families, though the specific history of this particular place remains, for now, incompletely documented in the public record.

The source material available for this site is, at present, too sparse to set out a detailed account of what stands or once stood at Earlstown, Cappasallagh. What can be said is that the location carries a formal archaeological designation, meaning it has been identified as significant enough to warrant recording and protection. Cappasallagh itself sits in the complex of townlands that make up rural County Galway, a county where the density of archaeological monuments, from ring forts and souterrains to medieval field systems, reflects thousands of years of continuous human activity. A souterrain, to note the term, is an underground stone-lined passage associated with early medieval settlement, sometimes used for storage or refuge. Whether the monument here is of that character, or something older or more recent, is a question the current public record cannot yet answer.