Leinster (lĕnˈstər, lĭnˈ–) [key], province (1991 pop. 1,860,949), 7,580 sq mi (19,632 sq km), E Republic of Ireland, comprising the counties of Carlow, Dublin, Kildare, Kilkenny, Laoighis, Longford, Louth, Meath, Offaly, Westmeath, Wexford, and Wicklow. It contains the capital of Ireland, Dublin. During the Middle Ages, the kings of Leinster fought against the kings of Meath. Its wealth and accessibility made the ancient province subject to Danish and Anglo-Norman invasions.