From Atlas and Cyclopedia of Ireland (1900)
NAME.—The town of Cavan (which gives name to the county) has its own name from the remarkable hollow in which it stands; Gaelic, Cabhan (pron. Cavan), a hollow—cognate with Latin cavea, and English cabin.
SIZE AND POPULATION.—From the main body of the county a long neck extends northwest. Taking this projection into the measurement, the extreme length from the northwest near Lough Macnean, to the southeast near Kingscourt, is 57 ½ miles, and its breadth from the southwest near Lough Kinale, to the northeast point near Cootehill, 27 miles; area, 746 square miles; population, 129,476.
SURFACE.—All the northwest projection, west of the Woodford River and Ballyconnell, is upland or mountainous—lofty, rugged, boggy and bleak. The rest of the county is a plain of undulations—a series of low round hills, with here and there a few considerable elevations, in many places much interspersed with lakes and bogs.
MOUNTAINS AND HILLS.—The chief summits in the northwest lie on the boundary. The highest is Cuilcagh (2,188), with its northern slope in Fermanagh, a fine mountain, rendered conspicuous in many of its aspects by the white quartz stones strewed over its surface. South of this, 1 ½ miles, is Binbeg (1,774). Tiltinbane (1,949) lies on the boundary with Fermanagh, 2 miles northwest of Cuilcagh; near its base the Shannon rises. These three, with several others, form a chain, which bounds on the northeast the fine valley of Glengavlin, traversed by the Owenmore River and the Shannon. On the southwest side of the valley are Benbrack (1,648), (between which and Cuilcagh is the Gap of Bellavalley, the entrance from the east to Glengavlin); and Slievenakilla (1,793), on the boundary, sloping on the Cavan side into Glengavlin, and on the Leitrim side to Lough Allen.
Four miles southeast of Cavan town rises the conspicuous hill of Slieve Glah (1,057); and Bruse Hill (851), near which is Bruse Hall, lies 5 miles west of Bellananagh.
In the eastern end of the county, 3 miles east of Bailieborough, is Cornasaus (1,027), a remarkable hill, with the little lakelet Loughanleagh, on its eastern slope, celebrated for its medicinal qualities.
RIVERS.—Several important rivers run through this county that belong only in small part to it. The Shannon rises in the northwest extremity. The source is a pool called Lugnashinna, near the western base of Tiltinbane Mountain, on the north side of Glengavlin: from this the river flows for 7 miles till it touches Leitrim; next it runs for a mile and a half on the boundary between Cavan and Leitrim; then it enters Leitrim; and after another mile and a half falls into Lough Allen. The Owenmore flows west through the valley of Glengavlin, and joins the Shannon about 2 miles below Lugnashinna. This is, properly speaking, the real head water or main stream of the Shannon, though it is not called by the name.
The Owenayle, running south on the western boundary line between Cavan and Leitrim, joins the Shannon just before the latter enters Lough Allen. The Claddagh rises, on the southeast slopes of Cuilcagh Mountain, and, flowing through Swanlinbar, enters Fermanagh for Lough Erne; it is joined at Swanlinbar by the Blackwater—called in the early part of its course the Owensallagh.
The Woodford River runs for the greater part through Cavan; issuing from Garadice Lough (in Leitrim), and flowing by Ballyconnell, it forms for the rest of its course—to Upper Lough Erne—the boundary between Cavan and Fermanagh. The Erne, from its source in Lough Gowna, to near where it enters Upper Lough Erne, belongs to this county.
The Annalee flows west into Lough Oughter, passing by the villages of Ballyhaise and Butlersbridge; in the early part of its course it is called the Annagh, flowing from Lough Sillan and through Lough Tacker, near Shercock. The Annalee is joined by the Dromore River, which rises in Dromore Lough, on the boundary of the county near Cootehill, and a little further on by the Bunnoe stream from the north. The Blackwater rises on the eastern slope of Benbrack, and flows southeast near the boundary with Leitrim till it enters Garadice Lough. The Inny, flowing through Lough Sheelin and Lough Kinale, forms for some distance the boundaries between this county and those of Meath and Westmeath.
The Meath Blackwater flows for 2 to 3 miles through Cavan from its source in Lough Ramor. The Moynalty River, flowing southeast from its source near Bailieborough, forms, for 5 to 6 miles, the boundary between Cavan and Meath, entering Meath 2 miles above Moynalty.
LAKES.—The center of the county, especially that portion occupied by the two baronies of Upper and Lower Loughtee, is broken up by innumerable small lakes, the intervening portions of land being thickly populated and well cultivated, and in many parts—especially along the lake shores—beautifully wooded. Lough Oughter is an extraordinary complication of water: a large lake broken up into a number of small sheets by promontories, peninsulas, and islands, of all shapes and sizes—wooded, verdant, and cultivated. It contains among others the islands of Eonish, Trinity (in which are the ruins of Trinity Abbey), and Inch: and on a rock in the midst of the lake stands Clogh-Oughter Castle in ruins.
On the southern boundary is Lough Sheelin, more than half of which belongs to Cavan, a beautiful lake, nearly 5 miles long by about 2 miles broad. Near this is the smaller Lough Kinale, of which less than half is in Cavan. Lough Gowna, which is very much broken up—something like Lough Oughter—lies on the southwestern boundary, and belongs in part to this county.
Lough Ramor, near the southeast border, is about 4 miles long, with an average width of | mile, and is diversified with a number of lovely little wooded islands.
In the east, near Shercock, is the pretty Lough Sillan, and the two smaller Loughs, Tacker and Barnagrow. Brackley Lough, nearly a square mile in extent, lies in the northwest, near the village of Bawnboy.
TOWNS.—Cavan (3,050), the county town, lies in a hollow overtopped by one of those round grassy hills so common in this part of the county, with the beautiful demesne of Farnham in its neighborhood. Cootehill (1,789), near the northeast boundary, is a neat, well-built town, in the midst of a beautiful district, well cultivated, and diversified with lakes and woods. Belturbet (1,807), on the Erne, between Lough Oughter and Lough Erne, is a prosperous little town, with a large distillery; communication by barges with Lough Erne, and through the Ulster Canal (which joins the Erne a little below the town) with Lough Neagh.
Bailieborough (1,091), in the east of the county, is a very neat town, with an unusual number of public institutions. Kingscourt (932) is at the extreme eastern corner, beside the finely wooded demesne of Cabra. Virginia (663) is a pretty little town, beautifully situated on the north shore of Lough Ramor; Ballyjamesduff (731) lies 6 miles west of Virginia. Arvagh (716) is prettily situated on the shore of the little lake Garty, at the western boundary. Killashandra (709), near the west shore of Lough Gowna, is perched on a ridge in the midst of a number of beautiful lakes.
MINERALS.—The Connaught coal field extends into Cavan, comprising a small portion of the county in the northwest, bordering on Lough Allen; and coal is found also near Kingscourt and near Shercock. The high land near Swanlinbar produces iron ore; and lead and copper ores are found near Cootehill.
ANCIENT DIVISIONS AND DESIGNATIONS.—This county was anciently called East Brefny or Brefny O'Reilly; for it was the patrimony of the O'Reillys: the county Leitrim forming West Brefny or Brefny O'Rourke. Croghan, near Killashandra, was the place where the O'Rourke used to be inaugurated prince of Brefny.
The plain lying round Ballymagauran, on the boundary with Leitrim, was the ancient Moyslecht, where the pagan Irish worshiped their chief idol Crom-Cruach. Here, according to the bardic history, the pagan monarch Tiernmas and three-fourths of the men of Ireland were killed in some supernatural way while worshiping Crom-Cruach. Many centuries after, the idol was destroyed by St. Patrick.