Below is a list of Plainfield NJ zip codes. For your research we have also included Plainfield Area Code, Time Zone, UTC and the local Union County FIPS Code. Each Plainfield New Jersey zip code has a center Longitude / Latitude point (the Plainfield center is -74.417297363281 / 40.615001678467). For your convenience we have also indicated if that zip code in Plainfield observes Daylight Savings time.