The Johnston Brief
The quick reference for Johnston, Iowa: the ZIP code, area code, county, and the handful of facts you came here to grab. Everything's on one page, and if you want the deeper numbers on population, housing, and taxes, we've linked those too.
Johnston, Iowa uses ZIP code 50131. The area code is 515, and the town is in Polk County, on the northwest side of the Des Moines metro, in the Central Time Zone.
Johnston is covered by a single primary ZIP code, 50131, which spans essentially the whole city. That is unusual for a suburb its size and makes addressing simple - one ZIP, one town. A handful of properties right on the city's edges can technically fall into a neighboring ZIP as boundaries and municipal lines meet, so if it matters (for a delivery or a form), check the exact address. Everything in 50131 shares the 515 area code and sits in Polk County.
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Johnston, Iowa uses ZIP code 50131. It is in the 515 area code and Polk County. A few properties on the city's edges can fall into an adjacent ZIP, so confirm by the exact address if it matters.
Area code 515, the code for Des Moines and central Iowa.
Polk County, Iowa's most populous county, on the northwest side of the Des Moines metro.
Central Time (CST in winter, CDT in summer), the same as the rest of Iowa.
Johnston's population is about 24,384, making it a mid-sized suburb of Des Moines.