Kittatinny Mountain is the dominant geological feature in the western section of the county. It is part of the Appalachian Mountains, and part of a ridge that continues as the Blue Mountain in Eastern Pennsylvania, and as Shawangunk Ridge in New York to the north. It begins in New Jersey as the eastern half of the Delaware Water Gap, and runs northeast to southwest along the Delaware River. Elevations range from to and attains a maximum elevation of at High Point, in Montague Township.: Between Kittatinny Mountain and the Delaware River is the Wallpack Ridge, a smaller, narrow ridge spanning in length from the Walpack Bend near Flatbrookville north to Port Jervis, New York. Wallpack Ridge encloses the watershed of the Flat Brook and its two main tributaries Little Flat Brook and Big Flat Brook, and ranges in elevation from to and reaching its highest elevation at .: