1 definition found niangua - U.S. Gazetteer (1990) : Niangua, MO (city, FIPS 52418) Location: 37.38765 N, 92.82973 W Population (1990): 459 (180 housing units) Area: 1.1 sq km (land), 0.0 sq km (water) Zip code(s): 65713