by Ninemile Creek and to the south by the Old Erie Canal, both of which are traversed by NY 173 on its way into the densely populated Fairmount neighborhood of Camillus. In Fairmount, NY 173 passes Reed Webster Park and turns to the east ahead of the Camillus Bypass, a limited-access highway carrying NY 5 through the town. NY 173 parallels NY 5 for about before connecting to westbound NY 5 by way of a partial interchange; the eastbound connection is made by way of Hinsdale Road (CR 209) to the west. East of the westbound on-ramps, NY 173 passes over NY 5 and turns to the southeast ahead of an intersection with NY 297. The route continues on through Fairmount, intersecting West Genesee Street (CR 98) before becoming Onondaga Road and exiting the neighborhood upon entering the town of Onondaga. Within Onondaga, NY 173 passes through both open areas with sparse development and areas containing built-up residential neighborhoods. The route heads southeast to Onondaga Hill, a large community built up just east of Onondaga Community College. Here, it overlaps with NY 175 for about before NY 175 forks off to the northeast into Syracuse. NY 173 continues eastward as the Seneca Turnpike, passing to the south of Community General Hospital before it enters the southernmost portion of Syracuse. This portion of the city is mostly residential, save for a smattering of businesses around NY 173's junctions with NY 80 and US 11. Near the midpoint of the route's stay in Syracuse, it crosses over Onondaga Creek, on the banks of which lie Faith Heritage School and Meachem Field. The route leaves the city limits shortly after passing under both directions of I-81. All of NY 173 west of Genesee Street in Camillus is maintained by Onondaga County. NY 173 is co-designated with CR 204 from NY 31 to Bennetts Corners Road in Van Buren, CR 64 between Bennetts Corners Road and Canton Street in the hamlet of Warners, CR 57 from Canton Street to Thompson Road in Camillus (note- a portion of former NY 57 in Onondaga County is signed as CR 57 but is officially part of CR 91), and CR 63 between Thompson Road and Genesee Street. Within Syracuse, NY 173 is maintained by the city. The remainder of the route in both Onondaga and Madison counties is maintained by the New York State Department of Transportation.