announced. The work was completed by 1942. Route 143 was extended northwards further into the park by 1955, and Route N was paved in asphalt by 1958. A new gravel road, Route NN, connected Routes 143 and N by 1964, after it was proposed in 1961. Route NN was paved by 1968, and Route 143 replaced Routes N and NN by 1970, with its northern terminus at Route 49. Major intersections References External links 143 Transportation in Wayne County, Missouri Transportation in Iron County, Missouri