Route designations may be repeated within a single county, depending on the size and population of the county. Designations may continue over a county line. Usually the letter designation remains the same when the route is a former Wisconsin state highway that has been decommissioned and turned over to county control. There is no east/west or north/south pattern restrictions on which letters can be used for a road, and they can be looped around counties and metropolitan areas. County highways can also hold concurrencies with state and U.S. highways; there are no current concurrencies with county highways and interstates.