ALTOONA, a town of the United States, in Blair county, Pennsylvania, on the Central Railway, 244 miles west of Philadelphia, situated near the eastern base of the Alleghany Mountain, where the railroad begins to ascend it. It contains extensive locomotive and railway carriage manufactories belonging to the Pennsylvania Central Railway Company. Near Altoona is the famous " Horse Shoe Bend," where trains of but ordinary length are seen to be moving in opposite directions at the same time. The line of railway, in its ascent between Altoona and Cresson, winds round the side of the mountain, affording some of the finest mountain scenery on the continent. Population in 1870, 10,610.