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 (NYSDOT).