O'Brien County, Iowa

O'Brien County is a county in Iowa with an estimated population of 14,012 in 2023. 6 cities, towns and Census places in it are indexed here.

Largest places in O'Brien County

About O'Brien County

O'Brien County is one of the counties of Iowa. County governments in Iowa handle local services such as courts, property records and elections; cities and towns inside the county run their own municipal services. Population figures come from the Census Bureau's Vintage 2023 estimates, which are updated annually.