Birr (from the ) is a town in County Offaly, Ireland. Once called Parsonstown, after the Parsons family who were local landowners and hereditary Earls of Rosse. It is also a parish in the Roman Catholic Diocese of Killaloe.Birr is a designated Irish Heritage Town with a carefully preserved Georgian heritage. Birr itself has graceful wide streets and elegant buildings. Many of the houses in John's Place and Oxmantown Mall have exquisite fanlight windows of the Georgian period.