03857 is zip code located in Newmarket, New Hampshire. The population is 9,002, making 03857 the largest zipcode in Newmarket and the 9th largest in Rockingham County.
There are 3 public schools in 03857 with an average Homefacts rating of B+. The total crime rate for Newmarket is low , and there are 6 registered sex offenders residing in the zip code 03857. Unemployment in 03857 is low.