CULLUMKILL, or GOLUMBKILL, a parish, in the barony of GRANARD, county of LONGFORD, and province of LEINSTER, 3 miles (W.) from Granard, on the road to Arvagh ; containing 8543 inhabitants. This parish is situated on Lough Gawnagh, commonly called Ernehead lake, which divides it into two parts, and is embellished with some very beautiful scenery. It contains 13,646 statute acres, of which several thousand are bog, and about 120 woodland. This is a mountain district, having large tracts of wasteland ; the crops are principally oats and potatoes. Near Derrycross is a slate quarry, which has never been worked ; and there are quarries yielding limestone of the best kind. Ernehead, the handsome seat of J. Dopping, Esq., stands delightfully on the edge of the lake, in a demesne well planted with fine timber ; and about two miles off, nearly surrounded by the lake, is Woodville, the seat of R. Lambert, Esq., commanding rich and extensive views of the lake and surrounding country ; here is also Frankfort, the seat of J. McEvoy, Esq. It is a vicarage, in the diocese of Ardagh, and is part of the union of Granard ; the rectory is impropriate in W. Fulke Greville, Esq. The tithes amount to £664. 12. 2-., which is equally divided between the impropriator and the vicar, The church stands nearly in the centre of the parish, and is in good repair, and ornamented with minarets : it was erected in 1829, by aid of a gift of £830 from the late Board of First Fruits. In the R. C. divisions the parish is the head of a union or district, comprising also the western part of the parish of Abbeylaragh, and containing three chapels, one on the townland of Aughnacliffe, one on that of Ballinnulty, and one on that of Mullinloughto. A school is about to be established in connection with the Ardagh Diocesan Society ; and about 600 boys and 260 girls are educated in ten private schools. A monastery of Canons Regular, founded about the middle of the fifth century by St. Columb, stood on Inchmore, or the Great Island, in Lough Gawnagh, on the confines of Cavan and Longford, partly in Abbeylaragh, and partly in Columbkill : the island consists of 20 or 30 acres, and is now uninhabited. This monastery was destroyed by the Danes in 804, but was restored, and continued to exist until the 15th century. On the borders of the lake are the remains of the castle of Rossduff : and near Dunbeggan are two druidical altars, one supported by two, and the other by three, upright stones. Near the church of Cullumkill is a beautiful specimen of jasper.