ALLEN, BOG OF, a group of morasses in Kildare, King's County, Queen's County, and Westmeath, Ireland. Clane bog, the eastern extremity, is within 17m. of Dublin, and the morasses ex tend westward almost to the Shannon. Their total area is about 238,50o acres. The tract of country to which the name is given is intersected by strips of dry cultivated land. The rivers Brosna, Barrow, and Boyne rise in the morasses, and the Grand and Royal canals cross them. The bog has a general elevation of 2 5of t. above sea level, and the average thickness of the peat beds is 2 5f t. It rests on clay and marl.