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

FM

Fair

Over: TANGEN CREEK

096082804, Winneshiek, IA

Built 1961 Load: 18.1 t ADT: 59

V 64

Fair

Over: CREEK

096102003, Winneshiek, IA

Built 1957 Load: 18.1 t ADT: 471

FM

Fair

Over: YELLOW RIVER N FORK

097073104, Winneshiek, IA

Built 1962 Load: 18.1 t ADT: 740

FM

Fair

Over: TROUT CREEK

097080504, Winneshiek, IA

Built 1962 Load: 18.1 t ADT: 894

FM

Fair

Over: TURKEY RIVER

097091808, Winneshiek, IA

Built 1955 Load: 18.1 t ADT: 658

FM

Fair

Over: STREAM

098082812, Winneshiek, IA

Built 1958 Load: 18.1 t ADT: 1,169

FM

Fair

Over: TEN MILE CREEK

098100102, Winneshiek, IA

Built 1952 Load: 18.1 t ADT: 236

FM

Fair

Over: TEN MILE CREEK BRANCH

098101302, Winneshiek, IA

Built 1968 Load: 18.1 t ADT: 410

FM

Fair

Over: CANOE CREEK

099072604, Winneshiek, IA

Built 1935 Load: 18.1 t ADT: 147

337TH ST

Fair

Over: CANOE CREEK BRANCH

099080103, Winneshiek, IA

Built 1971 Load: 18.1 t ADT: 265

FM

Fair

Over: CANOE CREEK BRANCH

099080205, Winneshiek, IA

Built 1971 Load: 18.1 t ADT: 265

POLE LINE RD

Fair

Over: SMALL STREAM

099092904, Winneshiek, IA

Built 1950 Load: 18.1 t ADT: 344

LOCAL ROAD

Fair

Over: CREEK

099101703, Winneshiek, IA

Built 1968 Load: 18.1 t ADT: 40

LOCAL ROAD

Fair

Over: DRAINAGE

100071003, Winneshiek, IA

Built 1969 Load: 18.1 t ADT: 70

FM

Fair

Over: SILVER CREEK

100092601, Winneshiek, IA

Built 1973 Load: 18.1 t ADT: 560

FM

Fair

Over: CREEK

100092803, Winneshiek, IA

Built 1962 Load: 18.1 t ADT: 560

FM

Fair

Over: PINE CREEK

100092804, Winneshiek, IA

Built 1962 Load: 18.1 t ADT: 120

FM

Fair

Over: PINE CREEK

100092901, Winneshiek, IA

Built 1962 Load: 18.1 t ADT: 560

FM

Fair

Over: CREEK

100101501, Winneshiek, IA

Built 1961 Load: 18.1 t ADT: 120

FM

Fair

Over: NISHNABOTNA RIVER

078350409, Audubon, IA

Built 1958 Load: 18.1 t ADT: 597

H14 120TH ST

Fair

Over: LOCAL CREEK

073051801, Henry, IA

Built 1920 Load: 18.1 t ADT: 120

MATHEWS ST

Fair

Over: DRAINAGE DITCH #70

000000000, Story, IA

Built 1969 Load: 18.1 t ADT: 1,626

HIDDEN VALLY DR

Fair

Over: ELK RUN

000000000, Hardin, IA

Built 1977 Load: 18.1 t ADT: 66

US 30

Fair

Over: DRAINAGE DITCH

1.7 mi E of E Jct US 59, Crawford, IA

Built 1958 Load: 18.1 t ADT: 4,670

US 34

Fair

Over: DRAINAGE

2.1 mi. W of Jct. SR W-55, Henry, IA

Built 1956 Load: 18.1 t ADT: 6,800

US 20 US 52

Fair

Over: DRAINAGE DITCH

0.8 MI. E OF JCT. SR Y21, Dubuque, IA

Built 1957 Load: 18.1 t ADT: 18,500

IA 127

Fair

Over: LITTLE BLOOMER CREEK

2.7 mi. E of E jct IA 183, Harrison, IA

Built 1940 Load: 18.1 t ADT: 460

IA 144

Fair

Over: STREAM

0.4 MILES N OF JCT SR P54, Boone, IA

Built 1941 Load: 18.1 t ADT: 1,690

US 30

Fair

Over: STREAM

2.5 mi. W of Jct. IA #1, Linn, IA

Built 1951 Load: 18.1 t ADT: 12,000

US 18

Fair

Over: STREAM

0.2 mi. W of SR M22, O'Brien, IA

Built 1959 Load: 18.1 t ADT: 3,210

IA 39

Fair

Over: NATURAL STREAM

2.6 mi. S of SR D59, Sac, IA

Built 1951 Load: 18.1 t ADT: 1,540

CHARLES CITY RD

Fair

Over: SMALL STREAM

094141804, Chickasaw, IA

Built 1930 Load: 18.2 t ADT: 300

LOCAL RD

Fair

Over: SHANGHAR CREEK

074322703, Adair, IA

Built 1960 Load: 18.2 t ADT: 15

FM

Fair

Over: SMALL STREAM

069182602, Appanoose, IA

Built 1961 Load: 18.2 t ADT: 130

FM

Fair

Over: WEST CEDAR

087310701, Calhoun, IA

Built 1955 Load: 18.2 t ADT: 5

140TH ST NE

Fair

Over: STREAM

081071603, Johnson, IA

Built 1977 Load: 18.2 t ADT: 663

LOCAL RD

Fair

Over: DRAINAGE

076290402, Madison, IA

Built 1962 Load: 18.2 t ADT: 15

NEST AVE

Fair

Over: OTTER CREEK OVERFLOW

098422802, Osceola, IA

Built 1954 Load: 18.2 t ADT: 103

LOCAL

Fair

Over: OTTER CREEK

098422902, Osceola, IA

Built 1949 Load: 18.2 t ADT: 41

LOCAL

Fair

Over: STREAM

099390901, Osceola, IA

Built 1954 Load: 18.2 t ADT: 46

LOCAL ROAD

Fair

Over: CAMP CREEK

079222305, Polk, IA

Built 1958 Load: 18.2 t ADT: 34

FM

Fair

Over: DRAINAGE

081220702, Polk, IA

Built 1967 Load: 18.2 t ADT: 439

LOCAL

Fair

Over: MCELHANEY CREEK

089431802, Woodbury, IA

Built 2007 Load: 18.2 t ADT: 50

BACKBONE ST PK

Fair

Over: MAQUOKETA RIVER

IN BACKBONE STATE PARK, Delaware, IA

Built 1976 Load: 18.2 t

CO RD

Fair

Over: EAST CEDAR CREEK

088313301, Calhoun, IA

Built 1920 Load: 18.3 t ADT: 769

LOCAL

Fair

Over: BR MUD CREEK

083102703, Benton, IA

Built 1972 Load: 18.3 t ADT: 15

LOCAL

Fair

Over: BR PRAIRIE CK

083112401, Benton, IA

Built 1978 Load: 18.3 t ADT: 50

LOCAL

Fair

Over: BR PRATT CK

086112602, Benton, IA

Built 1975 Load: 18.3 t ADT: 20

HARMON RD

Fair

Over: SPRING CREEK

87-11-27-01-10, Black Hawk, IA

Built 1948 Load: 18.3 t ADT: 39

HESS RD

Fair

Over: TRIB TO MILLER CREEK

87-13-25-02-10, Black Hawk, IA

Built 1961 Load: 18.3 t ADT: 20

Showing 1,301-1,350 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.