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.