State profile · Below median Poor share

Idaho 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 Idaho.

4,616
Public bridges
29.5%
Good condition
4.9%
Poor condition

Idaho holds 4,616 public highway bridges (#37 of 52 by inventory) with a 4.9% Poor share (#33 of 52 by Poor share).

That is 4.9% 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 20 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

4,616

Public highway bridges in Idaho

Good Condition

29.5%

1,363 bridges rated 7-9

-20.5pp vs 50% benchmark

Poor Condition

4.9%

226 bridges whose lowest applicable component is rated 0-4

-2.6pp vs national avg 7.5%

Idaho vs national bridge condition

Idaho - Good condition share 29.5%
National avg

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

Idaho - Poor-condition share 16.3%
National avg

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

Idaho 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: Idaho has 4,616 bridges and a 4.9% Poor-condition share in the 2024 NBI, rank #20 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 (%) ID, Public bridges in inventory (thousands): 4.6k · Poor-condition share (%): 4.9%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%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%IA, Public bridges in inventory (thousands): 23.7k · Poor-condition share (%): 19.16%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: Idaho has 4,616 bridges and a 4.9% Poor-condition share in the 2024 NBI, rank #20 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.

Idaho 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

4,616 37th of 54 higher than 17 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 Idaho

The highlighted point is Idaho: 4,616 bridges and 4.90% in Poor condition, rank #20 of 54 jurisdictions ordered from the lowest share upward. The five jurisdictions immediately above and below Idaho on that same Poor-share ordering:

  • Ohio: 26,729 bridges · 4.74% Poor
  • Colorado: 8,965 bridges · 4.82% Poor
  • Idaho: 4,616 bridges · 4.90% Poor
  • Indiana: 19,495 bridges · 5.22% Poor
  • Kansas: 24,894 bridges · 5.26% Poor

The full national sortable table lives on the rankings page.

Material families in Idaho

Exclusive FHWA material families across all 4,616 bridges in this state; continuous variants fold into the parent family. Orthogonal to the Poor-share scatter above.

Who maintains Idaho’s inventory

State agency holds 29.8% of the 4,616 public highway bridges filed under Idaho in the 2024 NBI, the agency-of-record split for this state, not a condition verdict.

When Idaho’s bridges were built

Pre-1950 construction accounts for 7.0% of the 4,616 bridges with a recorded original year in Idaho. Era bands are orthogonal to the Poor-share ranking above.

Condition Distribution

Idaho29.5%65.6%GoodFairPoor
Bridge inventory deck-condition mix - Idaho (FHWA NBI)

Counties (44)

Ada 299 Adams 87 Bannock 124 Bear Lake 34 Benewah 47 Bingham 263 Blaine 96 Boise 88 Bonner 104 Bonneville 213 Boundary 83 Butte 32 Camas 61 Canyon 292 Caribou 45 Cassia 116 Clark 40 Clearwater 88 Custer 128 Elmore 97 Franklin 23 Fremont 137 Gem 57 Gooding 80 Idaho 215 Jefferson 127 Jerome 110 Kootenai 154 Latah 115 Lemhi 112 Lewis 21 Lincoln 53 Madison 80 Minidoka 66 Nez Perce 71 Oneida 23 Owyhee 48 Payette 65 Power 70 Shoshone 260 Teton 37 Twin Falls 126 Valley 149 Washington 80

Idaho 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 Idaho on the same metric.

OH

Ohio

4.74% top marginal rate
Structure
Progressive
Burden @ $100K
$26,729

CO

Colorado

4.82% top marginal rate
Structure
Progressive
Burden @ $100K
$8,965
Selected

ID

Idaho

4.90% top marginal rate
Structure
Progressive
Burden @ $100K
$4,616

IN

Indiana

5.22% top marginal rate
Structure
Progressive
Burden @ $100K
$19,495

KS

Kansas

5.26% top marginal rate
Structure
Progressive
Burden @ $100K
$24,894

Bridges Needing Most Attention in Idaho

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

STC 6774;TETON HWY

Poor

Over: S.FK.TETON RIVER

0.5 N. TETON, Fremont, ID

Built 1977 Load: 0.9 t ADT: 1,200

RIVER ROAD

Poor

Over: VINSON WASH

2.0 N. 2.6 W. GRAND VIEW, Owyhee, ID

Built 1930 Load: 0.9 t ADT: 60

SWAMP ROAD

Poor

Over: CAMAS CREEK

1.5 S. 0.3 E. HILL CITY, Camas, ID

Built 1965 Load: 1.8 t ADT: 40

ELK SUMMIT RD

Poor

Over: SOUTH FORK SALMON RIVER

14.6 N 4.3 W YELLOW PINE, Valley, ID

Built 1934 Load: 1.8 t ADT: 10

ROAD 50343

Poor

Over: LOGAN CREEK

NO DATA ENTERED, Valley, ID

Built 1980 Load: 2.6 t ADT: 50

200 SOUTH ROAD

Poor

Over: CAMAS CREEK

1.9 S. 6.8 E. FAIRFIELD, Camas, ID

Built 1920 Load: 2.7 t ADT: 30

All Bridges in Idaho

JAMESTON ROAD

Good

Over: BUTTE ARM CANAL

3.8 S. 1.3 W. IDAHO FALLS, Bonneville, ID

Built 1958 Load: 28.1 t ADT: 1,200

N 3000 E

Good

Over: N.FK.TETON RIVER

4.6 N. 3.6 E. REXBURG, Madison, ID

Built 1976 Load: 28.1 t ADT: 70

N 3000 E

Good

Over: TETON ISLAND CANAL

4.4 N. 3.6 E. REXBURG, Madison, ID

Built 1977 Load: 28.1 t ADT: 110

S6780;SALEM CHURCH

Good

Over: SALEM CANAL

0.060 W. SUGAR CITY, Madison, ID

Built 2001 Load: 28.1 t ADT: 1,900

2000 W

Good

Over: N.FK.TETON RIVER

4.1 N. 1.5 W. REXBURG, Madison, ID

Built 1977 Load: 28.1 t ADT: 50

STC 6809;N 500 W

Good

Over: N.FK. LEIGH CREEK

0.6 N. 2.5 E. TETONIA, Teton, ID

Built 1977 Load: 28.1 t ADT: 680

BASELINE RD

Good

Over: TRAIL CREEK

1.0 S. 0.5 E. VICTOR, Teton, ID

Built 2003 Load: 28.1 t ADT: 20

SCOTT MTN ROAD

Good

Over: DEADWOOD RIVER

0.25 E DEADWOOD DAM, Valley, ID

Built 1982 Load: 28.1 t ADT: 30

LANDMARK/STANLEY

Good

Over: JOHNSON CREEK

23 N. DEADWOOD RESV, Valley, ID

Built 1999 Load: 28.1 t ADT: 30

W 3200 S

Good

Over: TEXAS SLOUGH CANAL

1.68 N THORNTON, Madison, ID

Built 1972 Load: 28.1 t ADT: 50

W 4500 N

Good

Over: ST ANTHONY CANAL

0.22 W PLANO, Madison, ID

Built 1990 Load: 28.1 t ADT: 10

STC5759;W MCKINLEY

Good

Over: GOVERNMENT CREEK

SMELTERVILLE ECL, Shoshone, ID

Built 2010 Load: 28.1 t ADT: 1,100

SHAW LANE

Good

Over: MIDDLE LINE CANAL

2.0 N. 1.1 E. GRANDVIEW, Elmore, ID

Built 2022 Load: 28.2 t ADT: 30

12166: CLYDE RD.

Good

Over: Little Lost River

.1 mi E of L Lost Rvr HWY, Butte, ID

Built 2003 Load: 28.2 t ADT: 25

4248: SHOSHONE CRE

Good

Over: Shoshone Creek

11.1 mi E of I93, Twin Falls, ID

Built 1985 Load: 28.2 t ADT: 25

FS ROUTE NO. 338

Good

Over: BIRD CREEK

BIRD CREEK, Shoshone, ID

Built 2001 Load: 28.2 t ADT: 40

FOREST RD. 221-2

Good

Over: SLATE CR

32 MI. FROM GRANGEVILLE, Idaho, ID

Built 1976 Load: 28.2 t ADT: 40

TRAIL CREEK ROAD

Good

Over: TRAIL CREEK

2 MI SSW DEADWOOD RSRVOIR, Valley, ID

Built 1981 Load: 28.2 t ADT: 5

TAMARACK FLAT ROAD

Good

Over: THIRD FORK

5.5 MI SW GRANITE PEAK, Gem, ID

Built 1970 Load: 28.2 t ADT: 15

FDR

Good

Over: BIG CASINO CREEK

BIG CASINO CAMPGROUND, Custer, ID

Built 1969 Load: 28.2 t ADT: 80

ROAD

Good

Over: NO FORK PACKSADDLE CREEK

NO DATA ENTERED, Teton, ID

Built 2009 Load: 28.2 t ADT: 50

CANAL ROAD

Good

Over: SAND CREEK CHANNEL

RIRIE DAM, Bonneville, ID

Built 1976 Load: 28.5 t ADT: 3

CANAL ROAD

Good

Over: RIRIE OUTLET CH WILLW CR

RIRIE OUTLET CHANNEL, Bonneville, ID

Built 1976 Load: 28.5 t ADT: 3

IRON CREEK ROAD

Good

Over: IRON CREEK

20 S. 4 W. SALMON, Lemhi, ID

Built 2010 Load: 28.5 t ADT: 50

3708: DEEP CREEK

Good

Over: Deep Creek

47.1 mi S of ID78, Owyhee, ID

Built 1983 Load: 28.5 t ADT: 25

FOREST ROAD 642

Good

Over: SO. FK. WHITE BIRD CREEK

NO DATA ENTERED, Idaho, ID

Built 2008 Load: 28.5 t ADT: 25

WILLOW CK.-CRKD.R.

Good

Over: CROOKED RIVER

7 MI NW DEER PARK, Boise, ID

Built 1970 Load: 28.5 t ADT: 5

LT. ANDERSON CK RD

Good

Over: ANDERSON CREEK

2 MI NE OF GARDEN VALLEY, Boise, ID

Built 1983 Load: 28.5 t ADT: 12

NFSR 50172

Good

Over: E FK WEISER RIVER

NO DATA ENTERED, Adams, ID

Built 2013 Load: 28.5 t ADT: 50

CANYON ROAD

Good

Over: W. BRANCH SAND CREEK

4.0 S. 0.3 E. IDAHO FALLS, Bonneville, ID

Built 1973 Load: 28.8 t ADT: 470

FS ROUTE NO. 638

Good

Over: GRANITE CREEK

GRANITE CREEK, Bonner, ID

Built 2010 Load: 28.8 t ADT: 50

FS ROUTE NO. 1341

Good

Over: NO DATA ENTERED

BOTTOM CREEK, Kootenai, ID

Built 2007 Load: 28.8 t ADT: 40

STORMY PEAK ROAD

Good

Over: EAST BOULDER CREEK

NO DATA ENTERED, Lemhi, ID

Built 1983 Load: 28.8 t ADT: 50

SH 11

Good

Over: OROFINO CREEK

0.4 S. PIERCE, Clearwater, ID

Built 1971 Load: 29.0 t ADT: 950

US 12

Good

Over: APRROACH RD;CATHOLIC CR.

9.3 E. LEWISTON, Nez Perce, ID

Built 1968 Load: 29.0 t ADT: 8,000

SH 52

Good

Over: LOWER PAYETTE CANAL

0.1 E. PAYETTE, Payette, ID

Built 1992 Load: 29.0 t ADT: 3,900

SH 55

Good

Over: PHYLLIS CANAL

3 W. NAMPA, Canyon, ID

Built 1973 Load: 29.0 t ADT: 19,000

SH 21

Good

Over: BOISE RIVER

NEAR DIVERSION DAM, Ada, ID

Built 1996 Load: 29.0 t ADT: 6,400

I 184

Good

Over: I 84;FLYING WYE IC

2.0 W. BOISE, Ada, ID

Built 2000 Load: 29.0 t ADT: 26,000

SMA 7343;CHERRY LN

Good

Over: TEN MILE CREEK

0.5 N. 3.5 W. MERIDIAN, Ada, ID

Built 1961 Load: 29.0 t ADT: 5,900

STC4749; OLD HWY 7

Good

Over: S.FK.COTTONWOOD CREEK

4.7N. 2.2W. GRANGEVILLE, Idaho, ID

Built 1977 Load: 29.0 t ADT: 820

PECAN LANE

Good

Over: DEER FLAT HIGHLINE CNL

1.2 S. 1.0 E. HUSTON, Canyon, ID

Built 1990 Load: 29.0 t ADT: 140

7TH AVE N.

Good

Over: INDIAN CREEK

IN NAMPA;7TH AVE N, Canyon, ID

Built 1978 Load: 29.0 t ADT: 8,000

W HARBOR DRIVE

Good

Over: CHANNEL OF SPOKANE RIVER

1.4 S. 2.6 E. POST FALLS, Kootenai, ID

Built 2000 Load: 29.0 t ADT: 500

W ANTELOPE;FR 137

Good

Over: ANTELOPE CREEK

1.0 S. 21.6 W. ARCO, Butte, ID

Built 1966 Load: 29.0 t ADT: 10

N 2300 E

Good

Over: S. BRANCH WILFORD CANAL

1.0 W. WILFORD, Fremont, ID

Built 1997 Load: 29.0 t ADT: 140

S BATES RD

Good

Over: TETON RVR (NICKERSON BR)

1.9 S. 2.7 W. DRIGGS, Teton, ID

Built 1990 Load: 29.0 t ADT: 40

FS ROUTE NO. 400

Good

Over: FLAT CREEK

19.1 MI FROM BABINS JCT., Shoshone, ID

Built 1976 Load: 29.2 t ADT: 40

NO DATA ENTERED

Good

Over: HOODOO CREEK

ELK SUMMIT-RD 111, Idaho, ID

Built 1950 Load: 29.2 t ADT: 30

FOREST ROAD 1172

Good

Over: RED RIVER

NO DATA ENTERED, Idaho, ID

Built 1961 Load: 29.2 t ADT: 40

Showing 3,301-3,350 of 4,616 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 Idaho'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. Idaho 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.