1 definition found eastchester - U.S. Gazetteer (1990) : Eastchester, NY (CDP, FIPS 21809) Location: 40.95816 N, 73.80782 W Population (1990): 18537 (7884 housing units) Area: 8.7 sq km (land), 0.2 sq km (water) Zip code(s): 10709