State profile · Above median Poor share

Iowa bridge safety

According to the Federal Highway Administration's 2024 National Bridge Inventory, condition ratings, load ratings, and Poor-condition shares for every public highway bridge in Iowa.

23,719
Public bridges
38.8%
Good condition
19.2%
Poor condition

Iowa holds 23,719 public highway bridges (#7 of 52 by inventory) with a 19.16% Poor share (#1 of 52 by Poor share).

That is 19.2% of the state's inventory, against an average of 7.5% across the 54 states and territories with Poor-rated bridges on file, which places it 53 of 54 ordered from the lowest Poor share upward. A bridge is rated Poor when its weakest applicable component scores 4 or below on the inspecting agency's 0-9 scale, so the category is a maintenance and funding signal rather than a closure order or a live crossing-safety verdict.

Inventory: FHWA NBI 2024 · last ETL August 2026

Total Bridges

23,719

Public highway bridges in Iowa

Good Condition

38.8%

9,213 bridges rated 7-9

-11.2pp vs 50% benchmark

Poor Condition

19.2%

4,544 bridges whose lowest applicable component is rated 0-4

11.6pp vs national avg 7.5%

Iowa vs national bridge condition

Iowa - Good condition share 38.8%
National avg

Share of bridges rated 7-9 on the FHWA 0-9 scale (deck, superstructure, substructure all good).

Iowa - Poor-condition share 63.9%
National avg

Lower is better. Bar maxes at 30% (worst-state ceiling). National average sits at 7.5%.

Iowa in the national condition pattern

Each point is a state or territory in the FHWA NBI; the highlighted point is this profile.

Inventory size and Poor-condition share are different measures: Iowa has 23,719 bridges and a 19.2% Poor-condition share in the 2024 NBI, rank #53 of 54 jurisdictions ordered from the lowest share upward. The dashed comparisons mark the national average state rate and the midpoint of the plotted inventory range; neither is a live safety or closure threshold. Scatter plot of 54 data points. 0%10%20%30%40% 0k20k40k60k Public bridges in inventory (thousands) Poor-condition share (%) IA, Public bridges in inventory (thousands): 23.7k · Poor-condition share (%): 19.16%AL, Public bridges in inventory (thousands): 16.2k · Poor-condition share (%): 3.35%AK, Public bridges in inventory (thousands): 1.7k · Poor-condition share (%): 7.89%AZ, Public bridges in inventory (thousands): 8.6k · Poor-condition share (%): 1.15%AR, Public bridges in inventory (thousands): 13k · Poor-condition share (%): 5.43%CA, Public bridges in inventory (thousands): 25.8k · Poor-condition share (%): 5.91%CO, Public bridges in inventory (thousands): 9k · Poor-condition share (%): 4.82%CT, Public bridges in inventory (thousands): 4.4k · Poor-condition share (%): 4.72%DE, Public bridges in inventory (thousands): 0.9k · Poor-condition share (%): 1.26%DC, Public bridges in inventory (thousands): 0.3k · Poor-condition share (%): 1.95%FL, Public bridges in inventory (thousands): 13k · Poor-condition share (%): 2.79%GA, Public bridges in inventory (thousands): 15.1k · Poor-condition share (%): 1.59%GU, Public bridges in inventory (thousands): 0k · Poor-condition share (%): 12.77%HI, Public bridges in inventory (thousands): 1.2k · Poor-condition share (%): 6.53%ID, Public bridges in inventory (thousands): 4.6k · Poor-condition share (%): 4.9%IL, Public bridges in inventory (thousands): 26.9k · Poor-condition share (%): 9.35%IN, Public bridges in inventory (thousands): 19.5k · Poor-condition share (%): 5.22%KS, Public bridges in inventory (thousands): 24.9k · Poor-condition share (%): 5.26%KY, Public bridges in inventory (thousands): 14.5k · Poor-condition share (%): 7.37%LA, Public bridges in inventory (thousands): 12.7k · Poor-condition share (%): 11.48%ME, Public bridges in inventory (thousands): 2.5k · Poor-condition share (%): 15.41%MD, Public bridges in inventory (thousands): 5.5k · Poor-condition share (%): 4.56%MA, Public bridges in inventory (thousands): 5.3k · Poor-condition share (%): 8.88%MI, Public bridges in inventory (thousands): 11.4k · Poor-condition share (%): 11.27%MN, Public bridges in inventory (thousands): 13.5k · Poor-condition share (%): 4.44%MS, Public bridges in inventory (thousands): 16.7k · Poor-condition share (%): 6.03%MO, Public bridges in inventory (thousands): 24.6k · Poor-condition share (%): 8.95%MT, Public bridges in inventory (thousands): 5.2k · Poor-condition share (%): 6.81%NE, Public bridges in inventory (thousands): 15.4k · Poor-condition share (%): 7.9%NV, Public bridges in inventory (thousands): 2.1k · Poor-condition share (%): 1.14%NH, Public bridges in inventory (thousands): 2.5k · Poor-condition share (%): 7.51%NJ, Public bridges in inventory (thousands): 6.8k · Poor-condition share (%): 6.01%NM, Public bridges in inventory (thousands): 4k · Poor-condition share (%): 4.51%NY, Public bridges in inventory (thousands): 17.6k · Poor-condition share (%): 9.43%NC, Public bridges in inventory (thousands): 19.2k · Poor-condition share (%): 6.76%ND, Public bridges in inventory (thousands): 4.3k · Poor-condition share (%): 10.98%OH, Public bridges in inventory (thousands): 26.7k · Poor-condition share (%): 4.74%OK, Public bridges in inventory (thousands): 22.9k · Poor-condition share (%): 7.7%OR, Public bridges in inventory (thousands): 8.3k · Poor-condition share (%): 4.61%PA, Public bridges in inventory (thousands): 23.3k · Poor-condition share (%): 12.58%PR, Public bridges in inventory (thousands): 2.4k · Poor-condition share (%): 13.92%RI, Public bridges in inventory (thousands): 0.8k · Poor-condition share (%): 15.2%SC, Public bridges in inventory (thousands): 9.5k · Poor-condition share (%): 6.17%SD, Public bridges in inventory (thousands): 5.9k · Poor-condition share (%): 16.36%TN, Public bridges in inventory (thousands): 20.4k · Poor-condition share (%): 4.41%TX, Public bridges in inventory (thousands): 56.7k · Poor-condition share (%): 1.23%UT, Public bridges in inventory (thousands): 3.1k · Poor-condition share (%): 2.91%VT, Public bridges in inventory (thousands): 2.9k · Poor-condition share (%): 2.9%VI, Public bridges in inventory (thousands): 0k · Poor-condition share (%): 29.17%VA, Public bridges in inventory (thousands): 14.1k · Poor-condition share (%): 3.39%WA, Public bridges in inventory (thousands): 8.5k · Poor-condition share (%): 5.45%WV, Public bridges in inventory (thousands): 7.3k · Poor-condition share (%): 18.64%WI, Public bridges in inventory (thousands): 14.4k · Poor-condition share (%): 6.52%WY, Public bridges in inventory (thousands): 3.1k · Poor-condition share (%): 6.51%
Inventory size and Poor-condition share are different measures: Iowa has 23,719 bridges and a 19.2% Poor-condition share in the 2024 NBI, rank #53 of 54 jurisdictions ordered from the lowest share upward. The dashed comparisons mark the national average state rate and the midpoint of the plotted inventory range; neither is a live safety or closure threshold.

Iowa vs all states by public bridge inventory

Where this state's FHWA NBI public-highway bridge count sits among every state and territory on PlainBridges

23,719 7th of 54 higher than 47 of 54 states

States and territories, banded by public bridge inventory size

Each bar is a band; taller bars hold more states. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.

Source FHWA National Bridge Inventory · 2024

Read the rank neighborhood for Iowa

The highlighted point is Iowa: 23,719 bridges and 19.16% in Poor condition, rank #53 of 54 jurisdictions ordered from the lowest share upward. The five jurisdictions immediately above and below Iowa on that same Poor-share ordering:

  • South Dakota: 5,887 bridges · 16.36% Poor
  • West Virginia: 7,348 bridges · 18.64% Poor
  • Iowa: 23,719 bridges · 19.16% Poor
  • Virgin Islands: 24 bridges · 29.17% Poor

The full national sortable table lives on the rankings page.

Material families in Iowa

Exclusive FHWA material families across all 23,719 bridges in this state; continuous variants fold into the parent family. Orthogonal to the Poor-share scatter above.

Who maintains Iowa’s inventory

State agency holds 17.7% of the 23,719 public highway bridges filed under Iowa in the 2024 NBI, the agency-of-record split for this state, not a condition verdict.

When Iowa’s bridges were built

Pre-1950 construction accounts for 12.4% of the 23,719 bridges with a recorded original year in Iowa. Era bands are orthogonal to the Poor-share ranking above.

Condition Distribution

Iowa38.8%42%19.2%GoodFairPoor
Bridge inventory deck-condition mix - Iowa (FHWA NBI)

Counties (99)

Adair 306 Adams 186 Allamakee 197 Appanoose 183 Audubon 206 Benton 374 Black Hawk 489 Boone 135 Bremer 266 Buchanan 316 Buena Vista 156 Butler 289 Calhoun 197 Carroll 249 Cass 295 Cedar 301 Cerro Gordo 266 Cherokee 248 Chickasaw 302 Clarke 168 Clay 151 Clayton 256 Clinton 372 Crawford 301 Dallas 199 Davis 165 Decatur 197 Delaware 293 Des Moines 176 Dickinson 84 Dubuque 346 Emmet 78 Fayette 362 Floyd 213 Franklin 228 Fremont 179 Greene 168 Grundy 289 Guthrie 263 Hamilton 165 Hancock 138 Hardin 241 Harrison 217 Henry 173 Howard 210 Humboldt 87 Ida 182 Iowa 241 Jackson 246 Jasper 382 Jefferson 157 Johnson 372 Jones 231 Keokuk 183 Kossuth 267 Lee 214 Linn 506 Louisa 151 Lucas 195 Lyon 276 Madison 225 Mahaska 225 Marion 217 Marshall 304 Mills 184 Mitchell 167 Monona 162 Monroe 130 Montgomery 210 Muscatine 144 O'Brien 264 Osceola 185 Page 196 Palo Alto 135 Plymouth 432 Pocahontas 201 Polk 545 Pottawattamie 557 Poweshiek 248 Ringgold 217 Sac 224 Scott 291 Shelby 207 Sioux 449 Story 296 Tama 337 Taylor 220 Union 169 Van Buren 156 Wapello 190 Warren 239 Washington 207 Wayne 163 Webster 190 Winnebago 55 Winneshiek 342 Woodbury 455 Worth 116 Wright 182

Iowa vs nearby ranks

Adjacent states by Poor-condition share (lower share = better)

States are ranked by the share of bridges whose lowest applicable component rating is 4 or below. This describes recorded condition; it does not measure funding effectiveness or live crossing safety. States here sit immediately above and below Iowa on the same metric.

SD

South Dakota

16.36% top marginal rate
Structure
Progressive
Burden @ $100K
$5,887

WV

West Virginia

18.64% top marginal rate
Structure
Progressive
Burden @ $100K
$7,348
Selected

IA

Iowa

19.16% top marginal rate
Structure
Progressive
Burden @ $100K
$23,719

VI

Virgin Islands

29.17% top marginal rate
Structure
Progressive
Burden @ $100K
$24

Bridges Needing Most Attention in Iowa

Six lowest-condition bridges in Iowa, ranked by the portal's composite display score. Inspection intervals are risk-based under current NBIS rules.

MAIN ST

Poor

Over: IOWA RIVER

089211800, Hardin, IA

Built 1936 Load: 0.0 t ADT: 1,858

SO MAIN ST

Poor

Over: CASCADE LANDING

000000000, Des Moines, IA

Built 1896 Load: 0.0 t ADT: 743

E 13TH ST

Poor

Over: OVER I.C.E. RR

000000000, Scott, IA

Built 1900 Load: 0.0 t ADT: 358

EMERSON ST

Poor

Over: DRAINAGE

000000000, Madison, IA

Built 1965 Load: 0.0 t ADT: 396

1ST AVE S

Poor

Over: 21ST ST & RR

089282000, Webster, IA

Built 1968 Load: 0.0 t ADT: 9,860

1ST ST

Poor

Over: DRAINAGE

D60500515, Audubon, IA

Built 1930 Load: 0.0 t ADT: 9

All Bridges in Iowa

LOCAL

Fair

Over: STEIN CREEK

084120601, Benton, IA

Built 1990 Load: 37.1 t ADT: 34

LOCAL

Fair

Over: PRAIRIE CK

086091901, Benton, IA

Built 1989 Load: 37.1 t ADT: 26

COUNTY ROAD

Fair

Over: PANTHER CREEK

079280801, Dallas, IA

Built 1988 Load: 37.1 t ADT: 21

FM

Fair

Over: N. BRANCH NORTH RIVER

077272804, Madison, IA

Built 1985 Load: 37.1 t ADT: 50

LIME KILN RD

Fair

Over: BIG CEDAR RIVER

098173403, Mitchell, IA

Built 1992 Load: 37.1 t ADT: 167

LOCAL

Fair

Over: MILLER CREEK

073173604, Monroe, IA

Built 1989 Load: 37.1 t ADT: 60

160TH STREET

Fair

Over: E TARKIO RIVER

069370609, Page, IA

Built 1986 Load: 37.1 t ADT: 45

LOCAL

Fair

Over: CYLINDER CREEK

096313101, Palo Alto, IA

Built 1991 Load: 37.1 t ADT: 81

LOCAL

Fair

Over: CROOKED CREEK

070293102, Ringgold, IA

Built 1952 Load: 37.1 t ADT: 5

FM

Fair

Over: INLET BLACKHAWK LK

086360903, Sac, IA

Built 1989 Load: 37.1 t ADT: 330

FM

Fair

Over: SOUTH RIVER

074251704, Warren, IA

Built 1986 Load: 37.1 t ADT: 100

BEARDSLEY STREET

Fair

Over: SM STREAM

077251200, Warren, IA

Built 1989 Load: 37.1 t ADT: 616

LOCAL

Fair

Over: DD# 219

092250601, Wright, IA

Built 1987 Load: 37.1 t ADT: 21

KILWORTH ST

Fair

Over: DAVIDS CREEK

000000000, Audubon, IA

Built 1994 Load: 37.2 t ADT: 73

IA 3

Fair

Over: LITTLE MAQUOKETA RIVER

0.4 mi. N of N Jct SR D10, Dubuque, IA

Built 1947 Load: 37.2 t ADT: 5,100

NB I-29

Fair

Over: ALLEN CREEK

1.9 MI. N OF JCT. US 30, Harrison, IA

Built 1967 Load: 37.2 t ADT: 7,750

SB US 169

Fair

Over: 2ND AVE S

At the Jct. Iowa 926, Webster, IA

Built 2010 Load: 37.2 t ADT: 3,550

FM

Fair

Over: LYTLE CREEK

087E22903, Dubuque, IA

Built 1992 Load: 37.2 t ADT: 260

FM

Fair

Over: WOLF CREEK BRANCH

086182401, Grundy, IA

Built 1989 Load: 37.2 t ADT: 59

FM

Fair

Over: BUCK CREEK

089252303, Hamilton, IA

Built 1975 Load: 37.2 t ADT: 240

COUNTY RD X-64

Fair

Over: MILL CREEK

083012813, Jones, IA

Built 1957 Load: 37.2 t ADT: 432

LOCAL RD

Fair

Over: S FORK CLANTON CREEK

074273304, Madison, IA

Built 1989 Load: 37.2 t ADT: 34

LOCAL

Fair

Over: WALNUT CREEK

075182204, Marion, IA

Built 1988 Load: 37.2 t ADT: 82

400TH

Fair

Over: BURR OAK CREEK

098160501, Mitchell, IA

Built 1975 Load: 37.2 t ADT: 59

450TH

Fair

Over: SMALL STREAM

099161101, Mitchell, IA

Built 1974 Load: 37.2 t ADT: 26

100TH ST

Fair

Over: DRAINAGE

073360605, Montgomery, IA

Built 1990 Load: 37.2 t ADT: 20

340TH STREET

Fair

Over: MIDDLE SILVER CREEK

076413504, Pottawattamie, IA

Built 1998 Load: 37.2 t ADT: 270

FM

Fair

Over: BRANCH SALT CREEK

085132002, Tama, IA

Built 1998 Load: 37.2 t ADT: 727

FM

Fair

Over: LEWIS CREEK

067081204, Van Buren, IA

Built 1985 Load: 37.2 t ADT: 200

FM

Fair

Over: WHITE BREAST

074222403, Warren, IA

Built 1988 Load: 37.2 t ADT: 500

LOCAL

Fair

Over: NORTH FORK YELLOW RIVER

096070304, Winneshiek, IA

Built 1984 Load: 37.2 t ADT: 29

LOCAL

Fair

Over: SMALL STREAM

097083606, Winneshiek, IA

Built 1900 Load: 37.2 t ADT: 39

LOCAL

Fair

Over: SMALL

098100306, Winneshiek, IA

Built 1978 Load: 37.2 t ADT: 88

LOCAL

Fair

Over: STREAM

075302801, Adair, IA

Built 2005 Load: 37.2 t ADT: 35

NB I-29

Fair

Over: HORSE CREEK

1.8 MI. N OF JCT. IA 2, Fremont, IA

Built 1972 Load: 37.2 t ADT: 6,050

5TH ST

Fair

Over: CEDAR RIVER

CITY BRIDGE NO. 8, Black Hawk, IA

Built 1967 Load: 37.3 t ADT: 7,280

IA 141

Fair

Over: PARADISE CREEK

1.4 mi. E of Jct SR M14, Crawford, IA

Built 1991 Load: 37.3 t ADT: 1,850

460TH ST

Fair

Over: STREAM

094371203, Clay, IA

Built 1994 Load: 37.3 t ADT: 41

LOCAL

Fair

Over: NATURAL CREEK

0993436, Emmet, IA

Built 1985 Load: 37.3 t ADT: 71

FM

Fair

Over: CREEK

084E10104, Jackson, IA

Built 1956 Load: 37.3 t ADT: 50

20TH AVE.

Fair

Over: BEERS CREEK

084011302, Jones, IA

Built 1970 Load: 37.3 t ADT: 34

30TH AVE

Fair

Over: CREEK

079E12702, Scott, IA

Built 1993 Load: 37.3 t ADT: 15

220TH AVE

Fair

Over: CREEK

079E42901, Scott, IA

Built 1921 Load: 37.3 t ADT: 150

288TH ST

Fair

Over: MUD CREEK OVERFLOW

080E22205, Scott, IA

Built 1991 Load: 37.3 t ADT: 45

FM

Fair

Over: EAST BRANCH PLATTE RIVER

072303003, Union, IA

Built 1979 Load: 37.3 t ADT: 89

FM

Fair

Over: STREAM

069201406, Wayne, IA

Built 1951 Load: 37.3 t ADT: 70

LOCAL

Fair

Over: SMALL STREAM

079E13402, Scott, IA

Built 1993 Load: 37.3 t ADT: 71

E 4TH ST

Fair

Over: VIRDEN CREEK

CITY CULVERT NO. 38C, Black Hawk, IA

Built 1970 Load: 37.3 t ADT: 2,679

CREEKWOOD DR

Fair

Over: CATFISH CREEK

W. OF MANSON RD., Dubuque, IA

Built 2006 Load: 37.3 t ADT: 549

BUS BROWN DR

Fair

Over: UNNAMED CREEK

East of Lincolnway, Harrison, IA

Built 2015 Load: 37.3 t ADT: 1,225

Showing 8,351-8,400 of 23,719 bridges

Related

All states → | National rankings → | Understanding conditions → | Retired SD term explained →
Data sourced from the FHWA National Bridge Inventory (NBI), latest released cycle. See our methodology for details. Retrieved and formatted by PlainBridges.

Disclaimer: This information is provided for informational purposes only and does not constitute professional advice. Data is sourced from the FHWA National Bridge Inventory (NBI). Poor condition is an inspection-record category, not a closure or unsafe-to-cross designation. Consult the bridge owner for current status.

Understanding Bridge Conditions

How FHWA rates bridge condition on a 0-9 scale.

Check Your Daily Bridges

How to look up bridge condition data for bridges on your route.

Read our methodology — how this data is sourced, computed, and verified.

What to do with this

Use Iowa's inventory picture to drill to a county or a specific span.

NBI condition ratings are inventory snapshots, not live crossing-safety verdicts.

Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. Iowa Good/Fair/Poor shares and county rollups on this page are computed from the same NBI extract as the national boards; no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2024 NBI release. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.