Several instances exist of the use of a letter suffix for spurs and alternate routes.
Only long-distance through roads, for the most part, are contained in Oswego County's highway system. All other local roads are part of the Town systems. Road names, where available, have been compiled below, although many are no longer in common use. In no case does any county route wholly enter the City of Oswego. Pulaski 3 Hannibal Street Dead end at Hannibal vill.