Less discussed is the earthwork that also sits within the site, a monument that tends to be overshadowed by its more photogenic neighbours and whose precise character remains formally undocumented in the public record.

Earthworks is a broad category in Irish archaeology, covering everything from the raised banks of a ringfort, a type of enclosed farmstead common throughout the early medieval period, to field boundaries, burial mounds, and the remnants of later enclosures. Without more specific information attached to this particular monument, it is difficult to say with confidence what function this example served or when it was constructed. Craggaunowen itself is associated with the Hunt collection and was developed as an archaeological park from the 1960s onward, with the tower house at its core dating to the medieval period. The landscape around it is layered, and earthworks of various kinds could belong to almost any era from the prehistoric to the post-medieval.