NY 156 reaches the hamlet of Knox, where it runs as a two-lane residential street through the center of the community. In the center of Knox, the route intersects with CR 252 (Rock Cave Road). Leaving the hamlet of Knox, NY 156 passes Knox Cemetery and parallels Beaverdam Creek and soon turning southeast. Now running southeast through Knox, the route crosses the southern terminus of CR 260 (Wilther Road) and the eastern terminus of CR 254. After a turn to the northeast, NY 156 intersects with the western terminus of NY 157 (Thompsons Lake Road). Continuing northeast through Knox, NY 156 passes the Altamont Reservoir, passing multiple reservoir-side residences.