NY 20N began at an intersection with US 20 and NY 174 in the town of Marcellus. The route headed north, overlapping NY 174 through the town of Marcellus into the village of Marcellus. At the time, the two routes entered the village on South Street and followed it north to Main Street. NY 20N and NY 174 turned east, following Main for a half-block to North Street. Here, NY 20N and NY 174 split, with NY 174 heading to the west and NY 20N proceeding east along NY 175, which began at this junction at the time of NY 20N's removal. NY 20N and NY 175 continued east to Onondaga, where NY 173 joined the two routes and created a three-route overlap for. At the east end of the overlap, NY 20N continued east along NY 173 into the southernmost section of Syracuse. Here, the two routes intersected NY 80 and US 11 and passed under Interstate 81 before exiting the city limits. Now in the town of De Witt, NY 20N and NY 173 met the northern terminus of NY 91 in the hamlet of Jamesville. The overlap between NY 20N and NY 173 ended to the east in the village of Manlius, where NY 92 and NY 20SY joined both routes just west of where NY 173 split from NY 20N and continued to the east. Outside of Manlius, NY 20N, NY 20SY and NY 92 headed southeast for to Cazenovia, where all three routes ended at US 20 adjacent to Cazenovia Lake and west of the village.
History
The portion of NY 20N from the intersection of NY 174 and NY 175 in the village of Marcellus to the junction of NY 92 and NY 173 in Manlius was part of the Seneca Turnpike. The turnpike was created in the 1800s and at the time was the longest in the state. The establishment of an alternate route to U.S. Route 20, which bypassed Syracuse to the south, began in 1933. Local restaurants, hotels and gas stations, along with the Syracuse Chamber of Commerce all demanded a route bearing the "20" number on it. This new route would be designated NY 20N, to be established in 1938. The route extended from the town of Marcellus to the village of Cazenovia and overlapped NY 174, NY 175, NY 173, and NY 92 upon assignment. All four of the routes that NY 20N originally overlapped were assigned as part of the 1930 renumbering of state highways in New York. A second, more northerly alternate route of US 20 in the Syracuse area was assigned in 1951 and designated as NY 20SY. From Manlius to Cazenovia, NY 20SY overlapped NY 20N and NY 92. Both NY 20N and NY 20SY were removed in 1961.
