WILLIAMSPORT, a city of the United States, the county seat of Lycoming county, Pennsylvania, is situated in the valley of the west branch of the Susquehanna river, amid the hills of the Alleghany plateau, and is entered by four railway lines,—the Northern Central, the Philadelphia and Erie, the Philadelphia and Reading, and the Corning, Cowanesque, and Antrim. The city is somewhat irregularly laid out, and the streets are mainly unpaved. The population in 1880 was 18,934; in 1870 it was 16,030. Williamsport owes its importance chiefly to its large lumber industry. The healthfulness of its climate and the beauty of the surrounding scenery have made it a popular summer resort in recent years.