NY 266 continues north on the West Side of Buffalo, crossing into a large interchange with I-190, NY 198 (the Scajaquada Expressway) and the southern terminus of NY 265 (Tonawanda Street). At this interchange, NY 266 turns northwest with Niagara Street along Scajaquada Creek and parallels I-190 into the Black Rock section of Buffalo. Soon after, the ramp from exit 12 crosses NY 266 at another Tonawanda Street and exit 13 junctions at Austin Street. The route continues northeast, crossing exit 14 at Ontario Street and entering the Riverside neighborhood of Buffalo. At Crowley Avenue, the route passes southwest of St. Francis Cemetery and Riverside Cemetery. Just north of the cemetery, the route crosses into the town of Tonawanda.