MONAGHAN, a county of Ireland in the province of Ulster, bounded E. by Armagh, S.E. by Louth, S. by Meath, S.W. by Cavan, W. by Fermanagh, and N. by Tyrone. The area is 319,741 acres, or about 496 sq. m. The north-western part of the country is included in the great central plain of Ireland; but to the south and east the surface is irregular, although none of the hills is of great elevation. The principal range is that of Slievebeagh, a rugged and barren tract extending into the county Fermanagh, its highest summit being 1254 ft. above sea-level. The principal rivers are the Finn, which rises near the centre of the county and passes into Fermanagh, and the Blackwater, which forms the boundary with Tyrone. The Ulster Canal passes the towns of Monaghan and Clones, affording communication between Lough Neagh and Lough Erne. In geological structure the county drops from the Upper Carboniferous outlier of Slievebeagh in the north-west to a Carboniferous Limestone area towards Monaghan town; but south of this a tumbled Silurian area stretches across the Cavan and Armagh borders. At Carrickmacross, an outlier of Carboniferous Limestone, Coal Measures (with poor seams of coal) and Trias is encountered. Gypsum has been quarried in the Trias, and lead ore was formerly mined in many places in the Silurian area. The Triassic clay furnishes excellent bricks. Eskers or glacial ridges occur at several places. The limestone is not only abundant and good, but from the position of the rocks it can be obtained at small expense in working. Freestone and slates are quarried in considerable quantities. The soil in the more level portions of the county is fertile where it rests on limestone, and there is also a mixed soil of deep clay, which is capable of high cultivation; but in the hilly regions a strong retentive clay prevails, which could be made productive only by careful draining and culture. Spade husbandry generally prevails. The proportion of tillage to pasturage is roughly as i to ij. Oats, potatoes and turnips are the principal crops, but the quantity grown decreases. The number of cattle, sheep, pigs, goats and poultry, on the other hand, increases or is well maintained. Linen is the only manufacture of consequence, but the cultivation of flax has almost died out. The Belfast and Clones line of the Great Northern railway crosses the county from north-east to west, passing the town of Monaghan, and the Dundalk and Clones line of the same company runs from southeast to west, with branches to Carrickmacross and to Cootehill (county Cavan).
The population (86,206 in 1801; 74,611 in 1901) decreases as rapidly as any county population in Ireland, and emigration is very heavy. The total includes about 73% of Roman Catholics, and about 12% each of Protestant Episcopalians and of Presbyterians. The principal towns are Monaghan (the county town, pop. 2932), Clones (2068), Carrickmacross (1874), Castleblayney (1576) and Ballybay (1208). Thecounty includes five baronies. Assizes are held at Monaghan, and quarter sessions at Carrickmacross, Castleblayney, Clones and Monaghan. The two county members sit for the north and south divisions respectively. The county is in the Protestant and Roman Catholic dioceses of Clogher.
The district now called the county Monaghan was included in the district of Uriel or Orgial, and long known as Macmahon's country. It was made shire ground under its present name by Sir John Perrot in the reign of Elizabeth. At Clones there is a round tower in good preservation, but very rude in its masonry ; another at Inishkeen is in ruins. Near Clones there are two large raths. Although there are several Danish forts there are no medieval castles of importance. The only monastic structure of which any vestiges remain is the abbey of Clones, which was also the seat of a bishopric. The abbey dates from the 6th century, but was rebuilt in the 14th century after destruction by fire.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)