1 definition found three oaks - U.S. Gazetteer (1990) : Three Oaks, MI (village, FIPS 79720) Location: 41.79933 N, 86.61274 W Population (1990): 1786 (744 housing units) Area: 2.5 sq km (land), 0.0 sq km (water) Zip code(s): 49128