Missouri Route 143

Around 1934, a gravel road that extended several miles eastwards from Route 49 in Des Arc was designated as Route N.[2][3] By 1937, another gravel road from Route 34 to Sam A. Baker State Park was constructed and designated as Route 101.[4][5] Route N was extended to the Iron–Wayne county line by 1940.[6][7] The road was renumbered to Route 143 by 1941,[7][8] and the Route 101 designation was reused for another highway in Ozark and Howell counties.[9] In late May of that year, a project to pave the entirety of Route 143 in oil aggregate treatment was announced.[10] The work was completed by 1942.[8][11] Route 143 was extended northwards further into the park by 1955,[12][13] and Route N was paved in asphalt by 1958.[14][15] A new gravel road, Route NN, connected Routes 143 and N by 1964.[16][17] Route NN was paved by 1968,[18][19] and Route 143 replaced Routes N and NN by 1970, with its northern terminus at Route 49.[20][21]