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

I 15 NBL

Fair

Over: GIBSON CANAL

5.5 S. BLACKFOOT, Bingham, ID

Built 1959 Load: 30.8 t ADT: 13,750

I 15 NBL

Fair

Over: BUTTE MARKET LAKE CANAL

4.6 S. ROBERTS, Jefferson, ID

Built 1968 Load: 30.8 t ADT: 3,050

I 15 SBL

Fair

Over: BUTTE MARKET LAKE CANAL

4.6 S. ROBERTS, Jefferson, ID

Built 1968 Load: 30.8 t ADT: 3,050

I 15 NBL

Fair

Over: CAMAS CREEK

4.6 N. HAMER, Jefferson, ID

Built 1963 Load: 30.8 t ADT: 1,700

US 20B

Fair

Over: US 20 NB-SB;S.RIGBY IC

0.5 S. RIGBY, Jefferson, ID

Built 1976 Load: 30.8 t ADT: 3,300

I 84B

Fair

Over: UPRR;N.HAMMETT RR OP

0.5 N. HAMMETT, Elmore, ID

Built 1973 Load: 30.8 t ADT: 1,700

SH 34

Fair

Over: BEAR RIVER;RIVERDALE BR

5.1 N. PRESTON, Franklin, ID

Built 1960 Load: 30.8 t ADT: 2,700

SH 34

Fair

Over: BEAR RIVER;CLEVELAND BR.

23.3 N. PRESTON, Franklin, ID

Built 1953 Load: 30.8 t ADT: 1,300

SH 51

Fair

Over: BRUNEAU RIVER SLOUGH

0.5 W. BRUNEAU, Owyhee, ID

Built 1955 Load: 30.8 t ADT: 1,200

SH 57

Fair

Over: LOWER W.BRANCH PRIEST R.

8.4 N. PRIEST RIVER, Bonner, ID

Built 1936 Load: 30.8 t ADT: 2,000

US 20

Fair

Over: GROVE CREEK

12.1 W. CAREY, Blaine, ID

Built 1971 Load: 30.8 t ADT: 1,800

I 84 EBL

Fair

Over: 1250 E GS

12.3 E. BURLEY, Cassia, ID

Built 1960 Load: 30.8 t ADT: 9,000

I 84 WBL

Fair

Over: 1250 E GS

12.3 E. BURLEY, Cassia, ID

Built 1960 Load: 30.8 t ADT: 9,000

I 84B ;FIRST AVE

Fair

Over: LITTLE CANYON CREEK

IN GLENNS FERRY;FIRST AVE, Elmore, ID

Built 1962 Load: 30.8 t ADT: 2,800

SH 75

Fair

Over: BEAVER CREEK

11.6 S. OBSIDIAN, Blaine, ID

Built 1974 Load: 30.8 t ADT: 750

US 95

Fair

Over: I 84 EB-WB;US 95 IC

23.2 W. CALDWELL, Payette, ID

Built 1960 Load: 30.8 t ADT: 9,700

US 95

Fair

Over: W.FK.GOOSE CREEK

0.7 N. NEW MEADOWS, Adams, ID

Built 1978 Load: 30.8 t ADT: 3,200

SH 3

Fair

Over: ST MARIES R(MASHBURN BR)

12.3 S. ST MARIES, Benewah, ID

Built 1961 Load: 30.8 t ADT: 1,700

I 184 WBL CONNECTR

Fair

Over: US 20-26;BOISE RV SLOUGH

IN BOISE;CHINDEN BLVD IC, Ada, ID

Built 1991 Load: 30.8 t ADT: 27,250

STC 1769;RIVER RD

Fair

Over: BEAR R;CHEESECAKE FAC BR

4.5 S. 2.5 W. GRACE, Caribou, ID

Built 1975 Load: 30.8 t ADT: 140

STC 3770;STAR RD

Fair

Over: BOISE RIVER(STAR BRIDGE)

0.8 S. STAR, Ada, ID

Built 1982 Load: 30.8 t ADT: 11,000

SMA7013;CLOVERDALE

Fair

Over: RIDENBAUGH CANAL

2.0 S. 2.8 E. MERIDIAN, Ada, ID

Built 1969 Load: 30.8 t ADT: 13,000

STC 5711;MOON PASS

Fair

Over: CHAMPION CREEK

5.7 S. 5.4 E. WALLACE, Shoshone, ID

Built 1949 Load: 30.8 t ADT: 210

STC5731;ST JOE RVR

Fair

Over: NORTH FORK ST. JOE RIVER

0.5 E. AVERY, Shoshone, ID

Built 1990 Load: 30.8 t ADT: 290

STC 5783;PENINSULA

Fair

Over: LOWER WEST BR. PRIEST R.

3.2N. 0.3E. PRIEST RIVER, Bonner, ID

Built 1975 Load: 30.8 t ADT: 750

STC 5804;WESTSIDE

Fair

Over: BALL CREEK

6.7N. 4.7W. BONNERS FERRY, Boundary, ID

Built 1990 Load: 30.8 t ADT: 300

STP 7151;N MAIN ST

Fair

Over: PORTNEUF RIVER

IN POCATELLO;MAIN ARTHUR, Bannock, ID

Built 1957 Load: 30.8 t ADT: 9,500

SMA 7166;1ST ST

Fair

Over: MEPPEN CANAL

IN IDAHO FALLS;1ST STREET, Bonneville, ID

Built 1980 Load: 30.8 t ADT: 17,000

SMA7316;HOLMES AVE

Fair

Over: IDAHO CANAL

IN IDAHO FALLS;HOLMES AVE, Bonneville, ID

Built 1990 Load: 30.8 t ADT: 19,500

SMA8353;16TH AVE N

Fair

Over: INDIAN CREEK

IN NAMPA;16TH AVE.N., Canyon, ID

Built 1969 Load: 30.8 t ADT: 20,000

TREASURE LANE

Fair

Over: MARSH CREEK

0.3 N. 3.1 W. DOWNEY, Bannock, ID

Built 1970 Load: 30.8 t ADT: 250

2-1/2 MILE ROAD

Fair

Over: I 15;2-1/2 MILE ROAD GS

5.8 N. POCATELLO, Bannock, ID

Built 1959 Load: 30.8 t ADT: 50

JAMESTON RD;N1100E

Fair

Over: LITTLE SAND CREEK

0.5 N. 3.0 E. SHELLEY, Bingham, ID

Built 1960 Load: 30.8 t ADT: 870

STC1837;W RIVER RD

Fair

Over: PEOPLES CANAL

5.6 N. 2.3 E. BLACKFOOT, Bingham, ID

Built 1954 Load: 30.8 t ADT: 1,300

SHEEPSKIN ROAD

Fair

Over: I 15;SHEEPSKIN ROAD GS

11.5 N. POCATELLO, Bingham, ID

Built 1960 Load: 30.8 t ADT: 30

SAND ROAD

Fair

Over: I 15;SAND ROAD GS

6.9 S. BLACKFOOT, Bingham, ID

Built 1959 Load: 30.8 t ADT: 250

FERRY BUTTE RD

Fair

Over: I 15;FERRY BUTTE ROAD GS

5.5 S. BLACKFOOT, Bingham, ID

Built 1959 Load: 30.8 t ADT: 2,250

STC 1759;OLD HW 30

Fair

Over: DRAIN DITCH

0.7 W. BANCROFT, Caribou, ID

Built 1977 Load: 30.8 t ADT: 150

50 WEST ROAD

Fair

Over: H CANAL

2.6S 0.1W BURLEY;220S-50W, Cassia, ID

Built 1989 Load: 30.8 t ADT: 450

STC 4698;E 600 N

Fair

Over: SOUTHSIDE CANAL

6.8 N. 3.3 E. DECLO, Cassia, ID

Built 1998 Load: 30.8 t ADT: 700

SUBLETT ROAD

Fair

Over: I 84 EB-WB;SUBLETT RD IC

AT SUBLETT, Cassia, ID

Built 1967 Load: 30.8 t ADT: 280

470 SOUTH ROAD

Fair

Over: MILNER GOODING CANAL

3.1 S. DIETRICH, Lincoln, ID

Built 1985 Load: 30.8 t ADT: 80

SHOESTRING ROAD

Fair

Over: KING HILL MAIN CANAL

1.0 S. 1.5 W. BLISS, Twin Falls, ID

Built 1977 Load: 30.8 t ADT: 10

STRAWBERRY ROAD

Fair

Over: WEISER RIVER

1.9 S. 4.9 W. NEW MEADOWS, Adams, ID

Built 1923 Load: 30.8 t ADT: 30

STATE SHED ROAD

Fair

Over: W.BR.GOOSE CREEK

0.2 N. 0.1 E. NEW MEADOWS, Adams, ID

Built 1955 Load: 30.8 t ADT: 210

LYNWOOD ROAD

Fair

Over: MORA CANAL

8.8 S. 1.6 W. NAMPA, Canyon, ID

Built 1998 Load: 30.8 t ADT: 90

BOISE AVE

Fair

Over: LITTLE CANYON CREEK

IN GLENNS FERRY, Elmore, ID

Built 1987 Load: 30.8 t ADT: 500

BUTTE ROAD

Fair

Over: SQUAW CREEK

0.4 S. 0.4 W. SWEET, Gem, ID

Built 2006 Load: 30.8 t ADT: 130

AILOR CUTOFF RD

Fair

Over: BIG BEAR CREEK

0.9 S. 2.3 W. DEARY, Latah, ID

Built 1978 Load: 30.8 t ADT: 50

LITTLE BEAR RIDGE

Fair

Over: LITTLE BEAR CREEK

0.1 N. 2.0 E. TROY, Latah, ID

Built 1965 Load: 30.8 t ADT: 350

Showing 1,701-1,750 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.