NY 309 begins at an intersection with NY 29A in downtown Gloversville. The route heads northward as Bleecker Street, passing large commercial buildings as it heads north through the city. At Spring Street—two blocks north of NY 29A—the surroundings become more residential as the commercial structures are replaced by homes. The route continues on, crossing Cayadutta Creek between 8th Avenue and McLaren Street before leaving Bleecker Street at 11th Avenue to follow an unnamed western extension of 11th Avenue. At this point, the amount of development along NY 309 drops substantially as it parallels Cayadutta Creek and heads northwestward out of the city limits. At this point, maintenance of the route shifts from the city of Gloversville to the New York State Department of Transportation. Now in the town of Johnstown, the route winds its way northwestward as it follows Cayadutta Creek through an area of hilly terrain south of Adirondack Park. Development along the route largely ends at the intersection with West State Street; however, a pair of isolated homes are situated on NY 309 about to the northeast ahead of an intersection with CR 122, an east–west highway that serves the Fulton County Infirmary a short distance to the west. The route continues to wind its way through the mountains to the hamlet of West Bush, where Cayadutta Creek ends amidst a small cluster of houses. The route turns north at this point, passing a handful of homes before leaving the community upon passing through a narrow pass between two hills. North of West Bush, the route rapidly ascends in elevation as it climbs up the side of a large mountain. Along this stretch, the route veers to the northwest and southeast as it heads through an area of wilderness. NY 309 crosses the Blue Line into Adirondack Park near the mountain's summit. Upon reaching the top of the mountain, the highway straightens out and heads northward for roughly across the hill's plateau. Upon reaching the other side, the road gradually descends in elevation as it passes by Mountain Lake and enters the town of Bleecker. The highway continues its northeastward descent into the small lakeside hamlet of Bleecker, where NY 309 ends at an intersection with Lily Lake Road. At this point, the roadway becomes CR 112.
History
Part of CR 112 was originally part of an old Indian trail that went from Johnstown to Hamilton County via Bleecker. At some point, part of the trail in the vicinity of Bleecker was converted into a plank road that served several locations and churches north of Bleecker. Meanwhile, NY 309 was assigned as part of the 1930 renumbering of state highways in New York to a connector highway between the city of Gloversville and the hamlet of Bleecker.
