Here is a list of Township with County Lettered Highways that are open (unless marked otherwise).
Adams (all lettered Highways and all township Roads)
Albany (all lettered Highway sand all township Roads)
Clarno (Limited routes)
Cadiz (all lettered Highways and all township Roads)
Decatur (all lettered Highways and all township Roads)
Exeter (all Lettered Highways)
Jefferson (limited letter Highways and all township Roads)
Monroe (Limited letter Highways and all Township Roads)
Mt Pleasant (all lettered Highways)
Spring Grove (limited lettered HighwayRoutes and all township Roads)
Sylvester (all lettered Highways)
Washington (all lettered Highways and all township roads)