AGHADERG, or AGHADERRICK, From A Topographical Dictionary of Ireland (1837) by Samuel Lewis

 a parish, partly in the barony of LOWER but chiefly in that of UPPER IVEAGH, county of DOWN, and province of ULSTER, on the road from Newry to Belfast; containing, with the towns of Loughbrickland and Scarvagh, 8981 inhabitants. This place formed part of the grant made by Queen Elizabeth, in 1585, to Sir Marmaduke Whitchurch, who built a castle on the shore of Loughbrickland, which was dismantled by Cromwell's army, and remained in ruins till 1812, when it was taken down and a dwelling-house erected on its site. In 1690 William III. encamped here with his army from the 14th to the 25th of June, on his march to the Boyne: vestiges of the camp may still be traced, and Dutch coins are frequently found in the neighbourhood. The parish, according to the Ordnance survey, comprises 13,919 statute acres, of which 119 1/4 are covered with water, and 11,772 are applotted under the tithe act; of waste and bog there is one acre to every twenty of arable land, and the pasture land is in the proportion of one to every five acres in tillage. The land is extremely fertile, and under a highly improved system of tillage: the bog is very valuable, being estimated at 32 guineas per acre. Great quantities of clay-slate are raised here for mending the roads and for building purposes; and slate quarries have been formerly worked, but are now discontinued.

The Newry Canal, in its progress to Lough Neagh, forms the western boundary of the parish and the county. There are two lakes; Loughbrickland, which forms the summit level of the canal, is skirted on its western shore by the road from Dublin to Belfast; Loughadian, near the western boundary of the parish, is rendered highly picturesque by the beautiful grounds and rich plantations of Union Lodge, the seat of W. Fivey, Esq. Among the other gentlemen's seats are Scarvagh House, the handsome residence of J. Lushington Reilly, Esq.; Loughbrickland-House, of N. C. Whyte, Esq.; Lisnagrade, of E. H. Trevor, Esq.; and Woodville House, of R. Boardman, Esq. The manufacture of linen is carried on to a considerable extent, many persons being employed at their own houses in weaving damask, diapers, drills, shirtings, and sheetings, for the Banbridge manufacturers. The living is a vicarage, in the diocese of Dromore, and in the patronage of the bishop; the rectory is united, by charter of the 7th of Jas. I., to the rectories of Seapatrick, Drumballyroney, and Tullylish, and part of those of Drumgooland and Magherally, together constituting the corps of the deanery of Dromore, in the patronage of the Crown. The tithes amount to £746. 14. 3., of which £497. 16. 2. is payable to the dean, and £248. 18. 1. to the vicar.

The gross annual value of the deanery, as returned by the Commissioners on Ecclesiastical Revenues, is £1483. 19. The church is a large handsome edifice, in the early English style, erected in 1688, and a lofty square tower surmounted by an octagonal spire of hewn stone was added to it, for which the late Board of First Fruits, in 1821, granted a loan of £500. The glebe-house is a handsome residence; the Board, in 1801, gave £100 towards its erection, and also purchased a glebe of 24 acres for the vicar. The R. C. parish is co-extensive with that of the Established Church, and is the benefice of the Vicar-general; there are two chapels, one in Loughbrickland, a large and handsome edifice, and a smaller at Lisnagead. There are three places of worship for Presbyterians, one near the lake in connection with the Synod of Ulster, another at Glascar with the Seceding Synod, and a third at Scarvagh, all of the first class; one for Covenanters near Scarvagh, and one for Primitive Methodists at Lough-brickland.

There are two public schools, in which are about 100 boys and 70 girls; and eleven private pay schools, in which are about 400 boys and 290 girls'. Some remains of an ancient church exist in the townland of Drumsallagh; and about half a mile to the south-west of Lough-brickland are three upright stones, called "the three sisters of Greenan," apparently the remains of an ancient cromlech: they are situated on a gentle eminence, and near them is a fourth lying in a ditch. In 1826, a canoe formed out of a solid piece of oak was found in Meenan bog; and in a small earthwork near it were found several gold ornaments, earthen pots, and other relics of antiquity. At Drummillar is a vast cairn of loose stones, 60 feet high and 226 feet in circumference.-- See LOUGHBRICKLAND and SCARVAGH.