Laois is a county in east central Ireland in Leinster Province, bounded on the northwest and north by County Offaly, on the east by County Kildare, on the southeast by County Carlow, on the south by County Kilkenny, and on the west by County Tipperary. Its area is 644 square miles.
In the northwest, the surface of the county is mountainous, with the Slieve Bloom range extending across the northwest corner, reaching a height of around 2000 feet. The principal rivers are the Barrow and the Nore. The Grand Canal, connecting Dublin with the River Shannon, crosses the northern part of the county. Throughout the county are the remains of several medieval castles, three or four fine examples of round towers, and a 12th-century abbey at Abbeyleix. Portlaoise, sometimes called Portlaoighise or Maryborough, is the county seat and largest town.
