1911 Encyclopædia Britannica/Delaware Water-Gap
DELAWARE WATER-GAP, a borough and summer resort of Monroe county, Pennsylvania, U.S.A., on the Delaware river, about 108 m. N. of Philadelphia and about 88 m. W. by N. of New York. Pop. (1890) 467; (1900) 469. It is served directly by the Delaware, Lackawanna & Western, and by the Belvidere division of the Pennsylvania railways; along the river on the opposite side (in New Jersey) runs the New York, Susquehanna & Western railway, and the borough is connected with Stroudsburg, Pa. (about 3 m. W. by N.) by an electric line. The borough was named from the neighbouring gorge, which is noted for the picturesqueness of its scenery, especially in winter, when the ice piles up in the river, sometimes to a height of 20 ft. Here the river cuts through the Kittatinny (Blue) Ridge to its base. On the New Jersey side is Mt. Tammany (about 1600 ft.); on the Pennsylvania side, Mt. Minsi (about 1500 ft.); the elevation of the river here is about 300 ft. The gap (about 2 m. long) through the mountain is the result of erosion by the waters of a great river which flowed northwards acting along a line of faulting at right angles to the strike of the tilted rock formations. The scenery and the delightful climate have made the place a popular summer resort. The borough was incorporated in 1889.
See L. W. Brodhead, The Delaware Water-Gap (Philadelphia, 2nd ed., 1870).