Below is a list of Buchanan County IA zip codes. For your research we have also included Buchanan County Area Code, Time Zone, UTC and the local County FIPS Code. Each Buchanan County Iowa zip code has a center Longitude / Latitude point (the Buchanan County center is -91.858001708984 / 42.50899887085). For your convenience we have also indicated if that zip code in Buchanan County observes Daylight Savings time.