Below is a list of Monmouth OR zip codes. For your research we have also included Monmouth Area Code, Time Zone, UTC and the local Polk County FIPS Code. Each Monmouth Oregon zip code has a center Longitude / Latitude point (the Monmouth center is -123.22899627686 / 44.850700378418). For your convenience we have also indicated if that zip code in Monmouth observes Daylight Savings time.