Cayan. I. The southernmost county of the province of Ulster, Ireland, bounded by the counties Fermanagh, Monaghan, Meath, West-meath, Longford, and Leitrim; area, 746 sq. m.; pop. in 1871, 140,555. The soil is wet and marshy, but with drainage it is rendered productive. The mountainous districts, which include a considerable part of the county, are barren. Coal, iron, lead, and copper are found; marl, fuller's earth, potter's and brick clays are plentiful. There are many mineral springs, of which that of Livalinbar is the most noted. Cavan was anciently called Breifne (Brenny), and was part of the territory of O'liourke, the Irish chief, the seduction of whose wife by Der-mot MacMurrogh, king of Leinster, was the immediate cause of the English invasion. It was first made shire ground toward the close of the 16th century. The county was divided into baronies among the native possessors, five falling to the lot of the O'Reilly family. The O'Reillys having forfeited their possessions by rebellion at the beginning of the 17th century, Cavan reverted to the British crown. It now returns two members to parliament. II. The county town, on the Dublin and Galway railway, 85 m. X. E. of Galway, and 65 m.
N. W. of Dublin: pop. about 3,000. Petty and quarter sessions, annual fairs, and a weekly market are held in the town. It contains a fine parish church, a Catholic chapel and nunnery, Presbyterian and Methodist meeting houses, a fever hospital, an infirmary, a royal endowed school, a barracks, and a public pleasure ground, bequeathed to the town by Lady Fernham.