Waltham, MA (city, FIPS 72600) Location: 42.38784 N, 71.24221 W Population (1990): 57878 (21723 housing units) Area: 32.9 sq km (land), 2.3 sq km (water) Waltham, MN (city, FIPS 67918) Location: 43.82075 N, 92.87520 W Population (1990): 170 (72 housing units) Area: 1.2 sq km (land), 0.0 sq km (water) Zip code(s): 55982