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

ROAD

Good

Over: WARM RIVER

NO DATA ENTERED, Fremont, ID

Built 2010 ADT: 50

EAST FORK ROAD

Good

Over: PARKS CREEK

2 W. YELLOW PINE, Valley, ID

Built 2010 Load: 8.2 t ADT: 40

NO DATA ENTERED

Good

Over: PANTHER CREEK

NO DATA ENTERED, Lemhi, ID

Built 1981 Load: 9.4 t ADT: 50

MORGAN CRK RD

Good

Over: MORGAN CREEK;NE.CHALLIS

9.3 N. 1.5 E. CHALLIS, Custer, ID

Built 1977 Load: 10.0 t ADT: 90

FS ROUTE NO. 209

Good

Over: LEIBERG CREEK

LIEBERG CREEK, Kootenai, ID

Built 1997 Load: 10.0 t ADT: 50

BRIDGE CK. ROAD

Good

Over: M.FK. PAYETTE RIVER

BOILING SPRINGS C.G., Valley, ID

Built 1956 Load: 10.7 t ADT: 20

M.FK.PAYETTE R. RD

Good

Over: SILVER CREEK

2 MI N TRAIL CREEK CG, Valley, ID

Built 1958 Load: 12.0 t ADT: 50

TRAPPER CK. ROAD

Good

Over: NORTH FORK BOISE RIVER

2.5 MI SW OF DEER PARK, Boise, ID

Built 1977 Load: 12.3 t ADT: 10

EDNA CK.-L.OWL RD.

Good

Over: CROOKED RIVER

8 MI EAST OF PILOT PEAK, Boise, ID

Built 1976 Load: 12.6 t ADT: 150

NFSR 50375

Good

Over: MONUMENTAL CK

NO DATA ENTERED, Valley, ID

Built 1985 Load: 12.6 t ADT: 50

NO DATA ENTERED

Good

Over: NO DATA ENTERED

NO DATA ENTERED, Idaho, ID

Built 2011 Load: 13.0 t ADT: 10

M.FK.PAYETTE R. RD

Good

Over: M.FK. PAYETTE RIVER

3 MI N TRAIL CREEK CG, Valley, ID

Built 1957 Load: 13.0 t ADT: 50

NO DATA ENTERED

Good

Over: NO DATA ENTERED

NO DATA ENTERED, Custer, ID

Built 1972 Load: 13.9 t ADT: 100

PRIVATE ROAD

Good

Over: MORES CREEK

6.2 S. 5.2 W. IDAHO CITY, Boise, ID

Built 1985 Load: 14.5 t ADT: 15

BRINDLEY ROAD

Good

Over: CAMAS CREEK

1.9 MI. SSW OF HDQTRS, Jefferson, ID

Built 1980 Load: 14.5 t ADT: 10

FS ROUTE NO. 2116A

Good

Over: BEAVER CREEK

BEAVER CREEK CAMPGROUND, Bonner, ID

Built 1986 Load: 14.6 t ADT: 50

SMA 9773;LINDER RD

Good

Over: BOISE RIVER;N. CHANNEL

0.7 S. 3.0 W. EAGLE, Ada, ID

Built 1992 Load: 15.4 t ADT: 19,500

MCCOY CREEK RD

Good

Over: MCCOY CREEK

12.0 S 5.4 E PALISADES, Bonneville, ID

Built 1978 Load: 15.4 t ADT: 50

FOREST ROAD 233

Good

Over: WILDHORSE CREEK

NEAR OROGRANDE SUMMIT, Idaho, ID

Built 1955 Load: 15.6 t ADT: 50

N.FK. BOISE R. RD.

Good

Over: MORES CREEK

2 MI EAST OF IDAHO CITY, Boise, ID

Built 1955 Load: 16.2 t ADT: 79

STC 1718;ARBON VLY

Good

Over: BANNOCK CR.;MICHAUD BR.

15.6 N. PAULINE, Power, ID

Built 1964 Load: 16.3 t ADT: 320

N 1700 E

Good

Over: EGIN CANAL

0.8 N. 1.0 E. EGIN, Fremont, ID

Built 1980 Load: 16.3 t ADT: 20

FS ROUTE 301

Good

Over: FISHHOOK CREEK

6 MI FROM AVERY ID, Shoshone, ID

Built 1975 Load: 16.5 t ADT: 50

FS ROUTE 218

Good

Over: RED IVES CREEK

AT RED IVES WORK CENTER, Shoshone, ID

Built 1936 Load: 16.5 t ADT: 50

FDR

Good

Over: SOUTH FORK BOISE RIVER

10 MILES WEST FEATHERVILE, Elmore, ID

Built 1956 Load: 16.8 t ADT: 50

GARDEN GULCH ROAD

Good

Over: LAPWAI CR;GARDEN GULCH

0.7 S. 0.1 E. LAPWAI, Nez Perce, ID

Built 1995 Load: 17.2 t ADT: 230

FS ROUTE 302

Good

Over: GRANITE CREEK

4 MI. FROM NORDMAN ID, Bonner, ID

Built 1952 Load: 17.2 t ADT: 50

NO DATA ENTERED

Good

Over: E.F. BIG CREEK

EAST FORK BIG CREEK, Shoshone, ID

Built 1994 Load: 17.5 t ADT: 50

FS ROUTE NO. 2646

Good

Over: N. CARIBOU CR

NORTH CARIBOU CREEK, Boundary, ID

Built 1987 Load: 17.5 t ADT: 50

ROARING RIVER ROAD

Good

Over: ROARING RIVER

4.5 MI WSW DUTCH CK CABIN, Elmore, ID

Built 1957 Load: 17.8 t ADT: 20

FDR

Good

Over: WOOD RIVER

4MILES WEST SNRA HQTS, Blaine, ID

Built 1959 Load: 17.8 t ADT: 50

STC 6743 (E 200 N)

Good

Over: MARKET LAKE CANAL

4.5 S. 0.7 E. ROBERTS, Jefferson, ID

Built 1959 Load: 18.1 t ADT: 760

MAIERS LANE

Good

Over: LEMHI RIVER

3.7 S. 2.9 E. LEMHI, Lemhi, ID

Built 1977 Load: 18.1 t ADT: 120

FS ROUTE 1013

Good

Over: GOLD CREEK

18 MI.FROM NORDMAN ID., Bonner, ID

Built 1965 Load: 18.1 t ADT: 50

ROAD 50260

Good

Over: TRAIL CREEK

MP 0.7 OF 50260, Valley, ID

Built 1991 Load: 18.1 t ADT: 50

FS ROUTE NO. 2443

Good

Over: SMITH CREEK

SMITH CREEK, Boundary, ID

Built 1964 Load: 18.5 t ADT: 50

1901: HERD CREEK

Good

Over: East Fork Salmon River

9 mi S of ID75, Custer, ID

Built 1964 Load: 18.8 t ADT: 25

LONG CREEK ROAD

Good

Over: CLEAR CREEK

4.5 MI NE OF LOWMAN ID, Boise, ID

Built 1980 Load: 18.8 t ADT: 20

SYMONS ROAD

Good

Over: PORTNEUF RIVER

3.9N. 0.6W.LAVA HOT SPRGS, Bannock, ID

Built 1986 Load: 19.1 t ADT: 30

BROXON ROAD

Good

Over: PORTNEUF RIVER

4.7N. 0.6W.LAVA HOT SPRGS, Bannock, ID

Built 1986 Load: 19.1 t ADT: 30

648 N 1250 E

Good

Over: MAIN SOUTHSIDE CANAL

7.4 N 4.0 E DECLO, Cassia, ID

Built 2011 Load: 19.1 t ADT: 100

S 2000 E

Good

Over: DARBY CREEK

3.3 S. 2.5 E. DRIGGS, Teton, ID

Built 2014 Load: 19.1 t ADT: 200

NO DATA ENTERED

Good

Over: WHITE CAP CR

NO DATA ENTERED, Idaho, ID

Built 1936 Load: 19.1 t ADT: 20

NO DATA ENTERED

Good

Over: SKULL CREEK

2.5 MI FROM ROAD 247, Clearwater, ID

Built 1967 Load: 19.1 t ADT: 50

CURTIS CUTOFF ROAD

Good

Over: CURTIS CREEK

2 MI WEST OF WARM LAKE, Valley, ID

Built 1963 Load: 19.1 t ADT: 5

FDR

Good

Over: BIG BOULDER CREEK

20 MILES UP EAST FORK S R, Custer, ID

Built 1980 Load: 19.1 t ADT: 50

N.FK. BOISE R. RD.

Good

Over: CROOKED RIVER

3 MI N OF BARBER FLAT, Boise, ID

Built 1957 Load: 19.8 t ADT: 40

HUNTER CK-CRKD. R.

Good

Over: BEAR CREEK

3.8 MI N.W. OF DEER PARK, Boise, ID

Built 1963 Load: 19.8 t ADT: 12

WHISTOCKEN RD

Good

Over: LITTLE HANGMAN CREEK

0.5 N. 0.8 E. TILMA, Benewah, ID

Built 1950 Load: 20.0 t ADT: 30

STAGECOACH ROAD

Good

Over: TRAIL CREEK

AT NAPLES, Boundary, ID

Built 2007 Load: 20.0 t ADT: 810

Showing 3,051-3,100 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.