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

NO DATA ENTERED

Fair

Over: DEEP CREEK

NO DATA ENTERED, Lemhi, ID

Built 1962 Load: 27.9 t ADT: 50

Dam Road

Fair

Over: CASCADE DAM SPILLWAY

CASCADE DAM, Valley, ID

Built 1947 Load: 28.0 t ADT: 100

IRR BIA RTE 15

Fair

Over: BLACKFOOT RIVER

19 KM N.E. OF BLACKFOOT, Bingham, ID

Built 1978 Load: 28.1 t ADT: 100

US 2

Fair

Over: JOHNSON CREEK

3.4 E. LACLEDE, Bonner, ID

Built 1970 Load: 28.1 t ADT: 5,500

US 2

Fair

Over: UPRR;MOYIE SPRINGS OP

IN MOYIE SPRINGS, Boundary, ID

Built 1965 Load: 28.1 t ADT: 2,500

I 86 EBL

Fair

Over: PORTNEUF RIVER

2.7 W. CHUBBUCK, Power, ID

Built 1968 Load: 28.1 t ADT: 6,500

I 86 WBL

Fair

Over: PORTNEUF RIVER

2.7 W. CHUBBUCK, Power, ID

Built 1968 Load: 28.1 t ADT: 6,500

I 15 NBL

Fair

Over: SMA 7461;E. TERRY ST

0.6 S. POCATELLO, Bannock, ID

Built 1964 Load: 28.1 t ADT: 13,000

I 15 SBL

Fair

Over: SMA 7461;E. TERRY ST

0.6 S. POCATELLO, Bannock, ID

Built 1964 Load: 28.1 t ADT: 13,000

SH 16

Fair

Over: MIDDLETON CANAL

14 S. EMMETT, Ada, ID

Built 1959 Load: 28.1 t ADT: 11,000

BLAINE ST

Fair

Over: OLD INDIAN CREEK CHANNEL

IN CALDWELL., Canyon, ID

Built 1966 Load: 28.1 t ADT: 10,500

US 20 EBL

Fair

Over: AMERICANA BLVD;15TH ST.

IN BOISE; MYRTLE STREET, Ada, ID

Built 1992 Load: 28.1 t ADT: 28,500

US 93

Fair

Over: BIG LOST RIVER

1 W. ARCO, Butte, ID

Built 1958 Load: 28.1 t ADT: 2,100

US 26

Fair

Over: IDAHO CANAL

IN IDAHO FALLS, Bonneville, ID

Built 1978 Load: 28.1 t ADT: 12,000

US 30

Fair

Over: I 184B WB-EB;FAIRVIEW RP

IN BOISE;FAIRVIEW RAMP, Ada, ID

Built 1968 Load: 28.1 t ADT: 10,500

US 30

Fair

Over: DEER CROSSING

4.7 E. LAVA HOT SPRINGS, Bannock, ID

Built 1976 Load: 28.1 t ADT: 4,300

SH 36

Fair

Over: BEAR RIVER

3.5 E. JCT SH 34 & SH 36, Franklin, ID

Built 1960 Load: 28.1 t ADT: 970

SH 52

Fair

Over: NOBLE CANAL

11.5 E. PAYETTE, Payette, ID

Built 1956 Load: 28.1 t ADT: 1,700

SH 55

Fair

Over: LOW LINE CANAL

5.5 N. MARSING, Canyon, ID

Built 1974 Load: 28.1 t ADT: 10,000

SH 55

Fair

Over: CLEAR CREEK

8 S. CASCADE, Valley, ID

Built 1933 Load: 28.1 t ADT: 4,200

US 20

Fair

Over: SILVER CREEK

4.7 W. CAREY, Blaine, ID

Built 1979 Load: 28.1 t ADT: 1,900

I 84 WBL

Fair

Over: C CANAL

15.1 W. BURLEY, Jerome, ID

Built 1966 Load: 28.1 t ADT: 11,750

I 84 WBL

Fair

Over: MILNER GOODING CANAL

12.5 W. BURLEY, Jerome, ID

Built 1966 Load: 28.1 t ADT: 11,750

I 90 EBL

Fair

Over: ATLAS ROAD GS

2.6 W. COEUR DALENE, Kootenai, ID

Built 1971 Load: 28.1 t ADT: 31,500

I 90 WBL

Fair

Over: ATLAS ROAD GS

2.6 W. COEUR DALENE, Kootenai, ID

Built 1971 Load: 28.1 t ADT: 31,500

US 93

Fair

Over: SNAKE RIVER; PERRINE BR.

0.6 N. TWIN FALLS, Twin Falls, ID

Built 1976 Load: 28.1 t ADT: 29,000

US 93

Fair

Over: TOWER CREEK

10.4 N. SALMON, Lemhi, ID

Built 1931 Load: 28.1 t ADT: 1,800

US 95

Fair

Over: E.FK.GOOSE CREEK

1.7 N. NEW MEADOWS, Adams, ID

Built 1978 Load: 28.1 t ADT: 3,200

US 95

Fair

Over: LITTLE SALMON RIVER

8.6 S. RIGGINS, Idaho, ID

Built 1962 Load: 28.1 t ADT: 2,500

US 95

Fair

Over: US 95 RAMP;WASHINGTON IC

3.0 N. LEWISTON, Nez Perce, ID

Built 1980 Load: 28.1 t ADT: 5,800

STC2765;BOB BARTON

Fair

Over: N CANAL

2.0 S. 0.6 W. JEROME, Jerome, ID

Built 1973 Load: 28.1 t ADT: 2,200

STC2863;600 WEST R

Fair

Over: D-9A DRAIN

3.5 N. PAUL, Minidoka, ID

Built 1979 Load: 28.1 t ADT: 2,000

STC 3730;RIVERSIDE

Fair

Over: DEER FLAT HIGH LINE CNL

1.8 N. 3.3 E. MARSING, Canyon, ID

Built 1986 Load: 28.1 t ADT: 970

STC3840; SWEET-OLA

Fair

Over: SQUAW CREEK

4.5 S. 0.7 W. OLA, Gem, ID

Built 1928 Load: 28.1 t ADT: 450

STC 3840;SWEET-OLA

Fair

Over: SQUAW CREEK;N.OLA BR.

0.5 N. OLA, Gem, ID

Built 1965 Load: 28.1 t ADT: 230

STC3854;BLK BRDG

Fair

Over: PAYETTE RIVER

2.0 N. NEW PLYMOUTH NCL, Payette, ID

Built 1963 Load: 28.1 t ADT: 640

STC 3988;ROSEBERRY

Fair

Over: LAKE FORK

0.8 W. DONNELLY, Valley, ID

Built 1965 Load: 28.1 t ADT: 3,000

LICK CREEK ROAD

Fair

Over: N. FK. LAKE FK. CREEK

8.3 E. MCCALL, Valley, ID

Built 1949 Load: 28.1 t ADT: 40

I 90B LOOP

Fair

Over: S.FK.COEUR DALENE RIVER

0.1 S. SILVERTON, Shoshone, ID

Built 1978 Load: 28.1 t ADT: 3,100

STC 6727;75TH EAST

Fair

Over: ANDERSON CANAL

4.0 E. 0.3 N. UCON, Bonneville, ID

Built 1954 Load: 28.1 t ADT: 850

STC 6768;4700 EAST

Fair

Over: DRY BED CANAL

0.5 E. 1.9 N. RIRIE, Jefferson, ID

Built 1965 Load: 28.1 t ADT: 1,500

STC6805;A-2 CLK CO

Fair

Over: DRY CREEK

4 N. 7 E. KILGORE, Clark, ID

Built 1969 Load: 28.1 t ADT: 150

STP 7151;BENTON ST

Fair

Over: S.1ST AVE;UPRR;BENTON OP

IN POCATELLO;BENTON ST., Bannock, ID

Built 1967 Load: 28.1 t ADT: 10,000

STC 7196;ROLLENDET

Fair

Over: BUTTE ARM CANAL

IN IDAHO FALLS;ROLLENDET, Bonneville, ID

Built 1943 Load: 28.1 t ADT: 5,700

SMA 8383;LONE STAR

Fair

Over: PHYLLIS CANAL

IN NAMPA;LONE STAR RD., Canyon, ID

Built 1973 Load: 28.1 t ADT: 18,000

SAGE HOLLOW

Fair

Over: FORT HALL MAIN CANAL

1.5 N. 1.0 E. TYHEE, Bannock, ID

Built 1980 Load: 28.1 t ADT: 100

STC1842;RISING RVR

Fair

Over: PEOPLES CANAL

5.1 N. 1.0 E. BLACKFOOT, Bingham, ID

Built 1993 Load: 28.1 t ADT: 550

800 EAST ROAD

Fair

Over: SAND CREEK

0.2 S. 2.2 E. FIRTH, Bingham, ID

Built 1972 Load: 28.1 t ADT: 150

PARK ROAD

Fair

Over: LITTLE SAND CREEK

1.8 N. 4.0 E. SHELLEY, Bingham, ID

Built 1978 Load: 28.1 t ADT: 930

STC 1840;WOLVERINE

Fair

Over: RESERVATION CANAL

1.5 S. 0.4 E. FIRTH, Bingham, ID

Built 1966 Load: 28.1 t ADT: 520

Showing 1,351-1,400 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.