Carlow (kär´lō), county (1991 pop. 40,942), 346 sq mi (896 sq km), SE Republic of Ireland. The chief towns are Carlow, the county seat; Bagenalstown, on the Barrow River, which forms much of the western boundary of the county; and Tullow, on the Slaney River which crosses the county from north to south. The granitic uplands of the Blackstairs Mts. in the southeast are a conspicuous feature in an otherwise fertile lowland region. Grain and sugar-beet farming, cattle raising, and dairying are regional occupations. There are also flour-milling, malting, and sugar-refining industries. The trains from Dublin to Kilkenny and Waterford travel through Carlow. Organized as a county in the early 13th cent., Carlow was strategically situated on the southern edge of the English Pale. In the 13th cent. it had palatinate privileges.

Carlow, town (1991 pop. 14,027), seat of Co. Carlow, SE Republic of Ireland, on the Barrow River. It is an agricultural market in a dairy region, with sugar refining, flour milling, brewing, and shoe manufacturing. There are ruins of a 12th-century castle. The town is also the seat of the Roman Catholic diocese of Kildare and Leighlin. Of strategic importance, Carlow was burned in 1405 and in 1577. In 1798 a fierce street battle was fought there by insurgent United Irishmen. St. Patrick's College for priests opened in 1798.