1 definition found marmarth - U.S. Gazetteer (1990) : Marmarth, ND (city, FIPS 50860) Location: 46.29586 N, 103.93392 W Population (1990): 144 (99 housing units) Area: 6.6 sq km (land), 0.0 sq km (water) Zip code(s): 58643