BIRR, or PARSONSTOWN  , a market-town of King's county, Ireland, on an acclivity rising above the Birr, and on a branch of the Great Southern & Western railway by which it is 87 m . W.S.W. from Dublin . Pop. of urban district (1901) 4438 . Cumberland Square, in which there is a Doric column surmounted by a statue of the duke of Cumberland, to commemorate the battle of Culloden, is the point from which the several principal streets diverge in regular form . The fine castle of Birr, beside its historical interest, has gained celebrity on account of the reflecting telescope erected here (1828-1845) by William, third earl of Rosse . This is 56 ft. in length and weighs 3 tons; and there is another smaller instrument . Among institutions the model and preparatory schools of the Brothers of the Presentation Order are noteworthy . There is a bronze statue by Foley of Lord Rosse (d . 1867) . Some trade is carried on in corn and timber, and in brewing and distilling . An abbey was founded at Birr by St Brendan (d . 573), to whom the present parish church is dedicated .

The district formed

part of Ely O'Carroll, and was not included in King's county till the time of James I . A great battle is said to have been fought near Birr in the 3rd century between Cormac, son of Cond of the Hundred Battles, and the people of Munster . The castle was the chief seat of the O'Carrolls . In the reign of James I. it and its appendages were assigned to Lawrence Parsons, brother of Sir William Parsons, surveyor-general . From him the alternative name of the town is derived . The castle was more than once besieged in the time of Cromwell, and was taken by Ireton in 165o . It also suffered assault in 1688 and 169o .