Lumberland is located within the Upper Delaware Scenic and Recreational River. Elevations range from approximately 600 feet near the Delaware River to over 1,300 feet above sea level on the bluffs overlooking the Delaware, and where the Catskill Mountains begin to rise in the northern reaches of the town. The terrain is largely mountainous and wooded, with the majority of residents settling close to or on main roads, such as New York State Route 97 (Upper Delaware Scenic Byway).