Iowa Bridge Infrastructure: A Complete Analysis

Iowa is home to 23,716 bridges spanning 99 counties, making it one of the most significant bridge inventories in the country. These bridges carry a combined 34,812,188 vehicle crossings every day. Here is a comprehensive look at the state of Iowa's bridge infrastructure based on the latest National Bridge Inventory data.

Iowa earns an overall infrastructure grade of F based on the percentage of its bridges in poor condition. Currently, 4,423 bridges (18.6%) are rated poor, compared to the national average of 6.7%. The average bridge in Iowa is 46 years old, younger than the national average of 48 years.

Of the state's 23,716 bridges, 9,329 are in good condition, 9,964 are fair, and 4,423 are poor. View the full breakdown on the [Iowa report card](/reports/iowa).

These are the bridges carrying the highest daily traffic volumes across Iowa. High-traffic bridges are critical infrastructure -- their condition directly affects the commutes of tens of thousands of drivers.

The following bridges have the lowest sufficiency ratings in Iowa. These structures are the most likely candidates for federal repair or replacement funding under the Bipartisan Infrastructure Law.

Iowa's oldest bridges tell the story of the state's transportation history. Some of these structures have been in continuous service for over a century.

Iowa's bridge infrastructure grade of F reflects both the current condition of the state's bridges and the scale of the challenge ahead. With an average bridge age of 46 years, many of these structures are approaching or past the 50-75 year design life typical of most bridges. The state's ability to maintain and replace aging bridges will determine whether conditions improve or deteriorate in the coming decade.

For county-by-county breakdowns, historical trends, and individual bridge profiles, visit the [Iowa state page](/bridges/iowa) or the [Iowa report card](/reports/iowa). You can also explore how Iowa compares to other states in our [state rankings](/blog/best-bridge-infrastructure-by-state-2025).