Iowa has 23,716 bridges on public roads, according to the FHWA National Bridge Inventory. Of those, 4,423 are rated in poor condition — a rate of 18.6% — 178% above the national average of 6.7%. Another 9,964 are in fair condition, while 9,329 are in good condition.
Use the interactive Iowa bridge map below to explore every bridge, color-coded by condition. Click any cluster to zoom in, then click an individual bridge for its route, structural ratings, year built, daily traffic, and last inspection date. Filter by condition using the checkboxes, or switch to satellite view to see bridges from above. For a national comparison, see the full US bridges interactive map.
Iowa Bridge Conditions by the Numbers
- 23,716 total bridges on public roads in Iowa
- 4,423 in poor condition (18.6%) — above the national average of 6.7%
- 9,964 in fair condition (42%)
- 9,329 in good condition (39.3%)
- Oldest bridge in the inventory: LOCAL-DEAD END, built 1876
Oldest Bridges in Iowa
The oldest bridges in Iowa date back to the 1870s. The ten oldest Iowa bridges still in the national inventory:
| Route / Facility | Crosses | Year Built | Condition |
|---|---|---|---|
| LOCAL-DEAD END | SKUNK RIVER | 1876 | Poor |
| LOCAL | BR DES MOINES RIVER | 1878 | Poor |
| SUTTON RD | WAPSIPINICON RIVER | 1879 | Poor |
| LOCAL 25TH ST | UPPER IOWA RIVER | 1880 | Poor |
| ASH ST | DES MOINES ST | 1882 | Fair |
| LOCAL | NORTH RACCOON RIVER | 1882 | Poor |
| LOCAL-CLOSED! | DD 81 | 1882 | Fair |
| MAIN STREET SOUTH | SMALL CREEK | 1886 | Poor |
| BRIDGE ST | TURKEY RIVER | 1889 | Fair |
| LOCAL | BEAVER CREEK | 1890 | Poor |
Most Concerning Iowa Bridges: Poor Condition and High Traffic
The bridges of greatest concern combine a poor structural rating with high daily traffic loads. These Iowa bridges carry the most vehicles per day while rated in poor condition:
| Route / Facility | Crosses | Daily Traffic | Year Built | Deck | Superstructure | Substructure |
|---|---|---|---|---|---|---|
| US 67 | MISS RVR RR & IA 461 | 26,500 vehicles/day | 1940 | Good (7) | Poor (4) | Fair (5) |
| IA 12 | BNSF RVR STS & IA 376 | 20,600 vehicles/day | 1936 | Fair (5) | Fair (5) | Poor (4) |
| WB I-80 | SUGAR CREEK | 18,050 vehicles/day | 1960 | Poor (4) | Poor (4) | Good (7) |
| FLEUR DR | OLD UP RR & SW 22ND | 15,634 vehicles/day | 1936 | Good (7) | Good (7) | Poor (4) |
| EASTERN AVE | DUCK CREEK | 15,300 vehicles/day | 1900 | Poor (4) | Poor (4) | Fair (5) |
How Iowa Bridge Conditions Are Assessed
Bridge condition in the NBI is determined by ratings of three structural components — deck, superstructure, and substructure — on a scale of 0 (failed) to 9 (excellent). A bridge is classified as good when all three components score 7 or above. It is classified as poor when any component scores 4 or below. Ratings of 5 or 6 on any component with no component below 5 result in a fair classification. Iowa DOT coordinates inspections across Iowa in line with FHWA standards, with most bridges inspected on a 24-month cycle.
Frequently Asked Questions
How many bridges in Iowa are in poor condition?
4,423 of Iowa’s 23,716 bridges are currently rated in poor condition by the FHWA National Bridge Inventory, a rate of 18.6%.
What is the oldest bridge in
The oldest bridge recorded in Iowa’s NBI inventory is LOCAL-DEAD END, built in 1876.
What does a poor bridge rating mean?
A poor rating means at least one of a bridge’s three key structural components — deck, superstructure, or substructure — has been rated 4 or below on the NBI 0-9 scale. A rating of 4 is defined as “poor condition,” and ratings of 3, 2, 1, or 0 indicate increasingly serious deterioration. Poor-rated bridges are not necessarily unsafe or closed, but they require priority attention and monitoring.
View all 624,000+ US bridges on the national interactive map
Compare with neighboring states: Illinois bridges map | Minnesota bridges map | Missouri bridges map | Nebraska bridges map | South Dakota bridges map | Wisconsin bridges map
