1 definition found west plains - U.S. Gazetteer (1990) : West Plains, MO (city, FIPS 78928) Location: 36.74135 N, 91.86299 W Population (1990): 8913 (4030 housing units) Area: 21.9 sq km (land), 0.0 sq km (water) Zip code(s): 65775