Kildare (county), an inland county of Ireland, in the province of Leinster, bounded by Co. Meath on the N., Dublin and Wicklow on the E., King's County and Queen's County on the W., and Carlow on the S.; area, 654 square miles. The surface is generally level, and the soil a productive clayey loam. The prevailing flatness is broken on the E.
border by offsets of the Dublin and Wicklow Hills, from 1,000 to 1,200 feet in height, and to the W. and N. of the town of Kildare by the Dunmurry and Red Hills and the Hill of Allen (676 feet), which rises abruptly from the Bog of Allen, a tract comprising about one-fifth of the entire county. The Boyne skirts the N.W., the Barrow the S.W. border, and the Liffey enters the county from Wicklow, afterwards curving round in a N.E. direction.
Kildare is intersected by the Great Southern and Western Railway and the Grand Canal. Agriculture is the principal industry, but woollen goods and paper are manufactured to some extent. Raths, round towers, crosses, and other antiquities abound.