MAHONAGH, or CASTLEMAHON, a parish, in the Glenquin Division of the barony of UPPER-CONNELLO, county of LIMERICK, and province of MUNSTER, 2 miles (S. E.) from Newcastle; containing 3846 inhabitants. This parish is intersected by the river Deel, and the road from Newcastle to Charleville: it comprises 12,262 statute acres, as applotted under the tithe act, which are in part very good, though some are cold, wet, and stiff, being chiefly pasture and meadow, constituting several large dairy farms; around the village is some good land tolerably well cultivated. The marshy land consists chiefly of exhausted bog, all reclaimable by drainage. The soil rests on a substratum of limestone, excellent quarries of which are worked at Shauragh and near the village. The village, which consists of 24 small houses, is on the eastern bank of the Deel, over which there is a good stone bridge. The principal seats are Mayne, the residence of Bryan Sheehy, Esq.; and Ballymakillamore, of Godfrey Massey, Esq. The living is a rectory and vicarage, in the diocese of Limerick, and in the patronage of the Earl of Devon: the tithes amount to £500; and there is a glebe of 13 acres at Castlemahon, and another of 8 acres adjoining the old churchyard of Aglish. The Protestant parishioners attend the church of Newcastle. In the R. C. divisions the parish is the head of a union or district, called Castlemahon, comprising this parish and Corcomohide, in which union there are three chapels, situated at Castlemahon, Foughanough or Feohonagh (both modern buildings), and a new chapel, erected in 1836 on the road-side between Newcastle and Drumcolloher, at an expense of £600. Darby O'Grady, Esq., gave £10 towards the belfry. About 50 children, are educated in a national school; and there are three private schools, in which are about 150 children. The ruins of a massive square tower, about 30 feet high, exist near Castlemahon and give name to that village. Near it is a curious circular building, with a high conical roof of stone; it was a strong fortress, erected about 1490 by the Fitzgeralds. Not far from this are the remains of the ancient church. At Mayne are traces of ancient buildings, supposed to have been ecclesiastical, though their present appearance indicates that it was a military position; they most probably formed a strong hold of the Knights-Templars, and were therefore partly military and partly ecclesiastical. There is a churchyard at Aglish, but no vestige of the church, which was sometimes called Aglish na Munni.