No stone, no timber, no silted outline. The only evidence that they ever existed is a line of seventeenth-century legal prose.

The Civil Survey of 1654 to 1656, a detailed land inquisition carried out under Cromwellian administration to assess confiscated Irish territories, recorded that to the lands of Beallanaha there belonged "fowerteene Iile weares upon the River Shannon as alsoe free piscarry upon the sd. river." Fish weirs were fixed structures, typically low walls or frameworks of timber and wicker built across or into a river to trap fish as the current pushed them through narrow gaps or into enclosed pools. Fourteen of them in one place suggests a substantial, organised fishery, and the attached right of "free piscarry", meaning the legal entitlement to fish freely in the river, signals that whoever held Beallanaha at that time controlled a commercially significant stretch of the Shannon. The survey was compiled as part of the broader process of redistributing Irish land to Cromwellian settlers and creditors, so the weirs were recorded precisely because they had economic value worth noting and, in due course, transferring.