Errigal/Truagh … a description from Lewis Topographical Dictionary of Ireland, pub. 1837

ERRIGAL-TROUGH, a parish, partly in the barony of CLOGHER, county of TYRONE, but chiefly in that of TROUGH, county of MONAGHAN, and province of ULSTER, 3 miles (S.S.W.) from Aughnacloy, on the road to Emyvale, and on the river Blackwater; containing 9321 inhabitants. It comprises 24,792 statute acres, according to the Ordnance survey, of which 21,174 are in Monaghan, and 102 are under water; 21,834 acres are applotted under the tithe act. About four-fifths of the lands are arable and pasture, and there is a great deal of mountain land used for grazing, and some bog on the western boundary: agriculture is improving. There is abundance of limestone and sandstone; and coal is supposed to exist in the SleabeaMountains, though it has not been worked. On the north-western confines of the parish is Lough More. A small factory for weaving linen has been recently erected here.

The gentlemen's seats are Fort Singleton, that of T. Singleton, Esq., situated in a well wooded demesne of 200 acres; Favour Royal, the handsome residence of J. Corry Moutray, Esq., erected near the site of the ancient house, which was destroyed by fire in 1823, and surrounded by a richly wooded demesne of 740 acres; and Laurel Hill, of W. H. Mayne, Esq.

The living is a vicarage, in the diocese of Clogher, and in the patronage of the Bishop; the rectory is appropriate to the see of Clogher: the tithes amount to £400, of which £215.7.8 is payable to the bishop, and the remainder to the incumbent. The glebe house stands on a glebe of 40 acres. The church is a very neat modern structure. A handsome cruciform church, in the later English style, with a square tower at the north-east angle, was erected in the demesne of Favour Royal, in 1838, at an expense of £1000, by J. C. Moutray, Esq., who has endowed it with £50 per annum, augmented with £30 per annum by the Ecclesiastical Commissioners; it is open to the public, there being no other church within three miles of Favour Royal, and is called St. Mary's, Portclare; the living is a donative, in the patronage of the founder. There is also a chapel in the eastern part of the parish.

The R.C. parish is co-extensive with that of the Established Church, and contains three chapels, one at Knockconnan, built in 1820, at an expense of £700; another on the townland of Drimbriston, built in 1823 at an expense of £500; the third, built in 1787, is in the townland of Mullyoden: the two first were erected, and the last repaired, through the exertions of the Rev. C. McDermot, the parish priest.

There is a national school at Moy; and there are three other public schools, of which one at Fort Singleton is supported by T. Singleton, Esq., who built the school-house, in which the curate of the parish performs divine service twice every Sunday. There are also four hedge, three Scriptural, and four Sunday schools.

In that portion of the parish which is in the county of Tyrone is a remarkable place called Altadawin, where it is said that St. Patrick assembled the first of his followers; it is a valley, 150 feet deep, through the centre of which a tongue of land of considerable altitude extends, and on the summit stands a large rock in the form of an altar, adjoining which is another rock, in the form of a chair. The valley is covered with trees, and a beautiful stream runs nearly through its centre. A royal residence of an independent prince of the O'Nial family is reported to have stood here formerly.