1 definition found rocklin - U.S. Gazetteer (1990) : Rocklin, CA (city, FIPS 62364) Location: 38.80240 N, 121.24027 W Population (1990): 19033 (7559 housing units) Area: 32.7 sq km (land), 0.0 sq km (water) Zip code(s): 95677