In 1911, the New York State Legislature created Route 3-a, an unsigned legislative route extending from the Pennsylvania state line at Port Jervis to Route 4 (later NY 17) in Hancock along the Delaware River. Very little of this highway actually existed in reality; by 1920, only of the long route had been built. In the 1930 renumbering of state highways in New York, the segment of former Route 3-a from Port Jervis to Callicoon was designated as NY 97, even though two sections of the route—between NY 42 at Sparrow Bush and Mongaup and from Pond Eddy to near the hamlet of Tusten—were still incomplete. The remainder of old Route 3-a north of Callicoon, which was fully constructed by 1930, became part of NY 17B. In 1932, then-Governor Franklin D. Roosevelt signed legislation designating NY 97 as the "Upper Delaware Scenic Byway".