State profile · Below national median SD

Idaho bridge safety

Condition ratings, load ratings, and structural-deficiency data for every public highway bridge in Idaho — drawn straight from the FHWA National Bridge Inventory.

1,742
Public bridges
33.3%
Good condition
5.5%
Poor condition
5.5%
Structurally deficient

Total Bridges

1,742

Public highway bridges in Idaho

Good Condition

33.3%

580 bridges rated 7-9

-16.7pp vs 50% benchmark

Poor Condition

5.5%

96 bridges rated 0-4

Structurally Deficient

5.5%

96 bridges flagged for repair priority

-1.5pp vs national avg 7.0%

Idaho vs national bridge condition

Idaho — Good condition share 33.3%
National avg

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

Idaho — Structurally deficient share 18.4%
National avg

Lower is better. Bar maxes at 30% (worst-state ceiling). National average sits at 7.0%.

Condition Distribution

Bridge inventory deck-condition mix — Idaho (FHWA NBI)

Idaho33.295063145809415%55.166475315729045%GoodFairPoorStructurally Deficient
Bridge inventory deck-condition mix — Idaho (FHWA NBI)

Counties (44)

Ada 81 Adams 42 Bannock 25 Bear Lake 13 Benewah 15 Bingham 75 Blaine 39 Boise 41 Bonner 47 Bonneville 50 Boundary 52 Butte 14 Camas 26 Canyon 77 Caribou 12 Cassia 38 Clark 18 Clearwater 65 Custer 81 Elmore 45 Franklin 4 Fremont 46 Gem 16 Gooding 25 Idaho 130 Jefferson 55 Jerome 26 Kootenai 60 Latah 26 Lemhi 73 Lewis 6 Lincoln 16 Madison 27 Minidoka 19 Nez Perce 19 Oneida 2 Owyhee 20 Payette 9 Power 13 Shoshone 139 Teton 13 Twin Falls 35 Valley 82 Washington 25

Idaho vs nearby ranks

Adjacent states on the structurally deficient leaderboard (lower share = better)

States are ranked by share of bridges flagged structurally deficient — the FHWA classification for any span where deck, superstructure, or substructure carries a condition rating of 4 or below. Lower percentages indicate stronger maintenance funding and inspection follow-through. States here sit immediately above and below Idaho on the same metric.

20

Kansas

5.25% top marginal rate
Structure
Progressive
Burden @ $100K
$23,867

56

Wyoming

5.41% top marginal rate
Structure
Progressive
Burden @ $100K
$3,181
Selected

16

Idaho

5.51% top marginal rate
Structure
Progressive
Burden @ $100K
$1,742

28

Mississippi

5.92% top marginal rate
Structure
Progressive
Burden @ $100K
$16,823

45

South Carolina

6.10% top marginal rate
Structure
Progressive
Burden @ $100K
$5,396

Bridges Needing Most Attention in Idaho

Six lowest-condition bridges in Idaho, ranked by composite NBI rating. Each is inspected at least every 24 months.

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

SWAMP ROAD

Poor

Over: CAMAS CREEK

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

Built 1965 Load: 1.8 t ADT: 40

ROAD 50343

Poor

Over: LOGAN CREEK

NO DATA ENTERED, Valley, ID

Built 1980 Load: 2.6 t ADT: 50

VADNAIS LANE

Poor

Over: CAMAS CREEK

1.9 S. 0.6 E. KILGORE, Clark, ID

Built 1981 Load: 2.7 t ADT: 50

2701: NORTH MILNER

Poor

Over: Milner Gooding Canal

5.0 mi N of Hunt Rd, Jerome, ID

Built 1960 Load: 4.2 t ADT: 25

MIDDLE FORK ROAD

Structurally Deficient

Over: M.FK.WEISER RIVER

7.3 W 3.4 S DONNELLY, Adams, ID

Built 1957 Load: 4.5 t ADT: 70

All Bridges in Idaho

FS ROUTE NO. 320

Fair

Over: HELLER-SHERLOCK CREEK

HELLER SHERLOCK CR, Shoshone, ID

Built 1953 Load: 16.5 t ADT: 50

FDR

Fair

Over: WARM SPRINGS CREEK

14 MILES WEST KETCHUM, Blaine, ID

Built 1952 Load: 16.8 t ADT: 50

E. VIRGINIA ROAD

Fair

Over: MARSH CREEK

0.7 N. 1.7 W. VIRGINIA, Bannock, ID

Built 1959 Load: 17.2 t ADT: 150

SMA 7436; AMMON RD

Fair

Over: SAND CREEK

0.5 N. LINCOLN, Bonneville, ID

Built 1966 Load: 17.2 t ADT: 7,600

BOISE STREET

Fair

Over: MILL SLOUGH

AT MIDDLETON SCL, Canyon, ID

Built 1981 Load: 17.2 t ADT: 200

STC 3809;MIDDLE FK

Fair

Over: M.FK.BOISE RIVER;LOFTUS

6.2 S. 12.1 W.DUTCH CR RS, Elmore, ID

Built 1962 Load: 17.2 t ADT: 30

MOSER ROAD

Fair

Over: COW CREEK

1.5 S. 4.4 W. GENESEE, Nez Perce, ID

Built 1970 Load: 17.2 t ADT: 30

LIGHTENING CR RD

Fair

Over: M. FK. PAYETTE

8 MI NORTH OF CROUCH ID, Boise, ID

Built 1964 Load: 17.5 t ADT: 50

FS ROUTE NO. 2236

Fair

Over: GROUSE CREEK

GROUSE CREEK, Bonner, ID

Built 1971 Load: 17.5 t ADT: 50

CUSTER MOTORWAY

Fair

Over: YANKEE FORK

NO DATA ENTERED, Custer, ID

Built 2004 Load: 17.5 t ADT: 100

FOREST ROAD 421

Fair

Over: MALLARD CREEK

NO DATA ENTERED, Idaho, ID

Built 1992 Load: 17.5 t ADT: 50

NO DATA ENTERED

Fair

Over: COUGAR CREEK

NO DATA ENTERED, Valley, ID

Built 1970 Load: 17.5 t ADT: 50

ROAD

Fair

Over: PALISADES CREEK

NO DATA ENTERED, Bonneville, ID

Built 1975 Load: 17.8 t ADT: 50

FS ROUTE NO. 300A

Fair

Over: N.F. ST JOE RIVER

3.5 MILES FROM AVERY, ID, Shoshone, ID

Built 1935 Load: 17.8 t ADT: 50

505-3330E

Fair

Over: GRAYS LAKE OUTLET

2.4 S. 27.7 E. FIRTH, Bingham, ID

Built 1947 Load: 18.1 t ADT: 10

FDR

Fair

Over: WARM SPRINGS CREEK

6 MILES WEST OF KETCHUM, Blaine, ID

Built 1954 Load: 18.1 t ADT: 50

FDR

Fair

Over: SOUTH FORK BOISE RIVER

MOUTH BIG SMOKY CREEK, Camas, ID

Built 1951 Load: 18.1 t ADT: 50

STC3790;ALLENDALE

Fair

Over: LOW LINE CANAL

3.7 S. 2.O E. WILDER, Canyon, ID

Built 1939 Load: 18.1 t ADT: 240

200 SOUTH ROAD

Fair

Over: 'J' CANAL

1.0S 1.2E DECLO;970E-200S, Cassia, ID

Built 1984 Load: 18.1 t ADT: 110

CEMETARY RD

Fair

Over: JIM FORD CREEK

0.6 S. 0.3 E. WEIPPE, Clearwater, ID

Built 1975 Load: 18.1 t ADT: 50

20082

Fair

Over: WARM RIVER

NO DATA ENTERED, Fremont, ID

Built 1984 Load: 18.1 t ADT: 50

ROCK CREEK ROAD

Fair

Over: RED ROCK CREEK

9.5 S. 6.4 W. KAMIAH, Idaho, ID

Built 1970 Load: 18.1 t ADT: 200

FS ROUTE NO. 257

Fair

Over: STEAMBOAT CREEK

STEAMBOAT CR. @ OMAHO CR., Shoshone, ID

Built 1956 Load: 18.1 t ADT: 50

DEADWOOD ROAD

Fair

Over: DEADWOOD RIVER

1 N. DEADWOOD RESV, Valley, ID

Built 1959 Load: 18.1 t ADT: 30

ROAD

Fair

Over: BURNS CREEK

NO DATA ENTERED, Bonneville, ID

Built 1974 Load: 18.5 t ADT: 50

FS ROUTE NO. 661

Fair

Over: TOOT CREEK

TOOT CREEK, Boundary, ID

Built 1987 Load: 18.5 t ADT: 50

FOREST ROAD 309

Fair

Over: MILL CREEK

2.9 MI. FROM STATE HWY 14, Idaho, ID

Built 1966 Load: 18.5 t ADT: 30

FOREST ROAD 1150

Fair

Over: RED RIVER

NO DATA ENTERED, Idaho, ID

Built 1959 Load: 18.5 t ADT: 10

FS ROUTE NO. 208

Fair

Over: CDA RIVER

25.5 MI FROM BABINS JCT., Shoshone, ID

Built 1974 Load: 18.5 t ADT: 50

FDR

Fair

Over: WARM SPRINGS CREEK

10 MILES WEST OF KETCHUM, Blaine, ID

Built 1953 Load: 18.8 t ADT: 50

OKEEFE CREEK ROAD

Fair

Over: CLEAR CREEK

6.5 MI NNE OF LOWMAN, ID, Boise, ID

Built 1966 Load: 18.8 t ADT: 10

FS ROUTE NO. 314

Fair

Over: BOULDER CREEK

BOULDER CREEK, Boundary, ID

Built 1957 Load: 18.8 t ADT: 50

BEAVER CREEK ROAD

Fair

Over: BEAVER CREEK

NO DATA ENTERED, Custer, ID

Built 1953 Load: 18.8 t ADT: 50

CAMPGRD. ACCESS

Fair

Over: SOUTH FORK PAYETTE RIVER

KIRKHAM HOT SPRINGS CG., Boise, ID

Built 1966 Load: 19.1 t ADT: 60

SMA 7406;17TH ST

Fair

Over: IDAHO CANAL

IN IDAHO FALLS, Bonneville, ID

Built 1969 Load: 19.1 t ADT: 24,000

SKULL CANYON ROAD

Fair

Over: BIRCH CREEK

0.5 N. BLUE DOME, Clark, ID

Built 2001 Load: 19.1 t ADT: 10

FDR

Fair

Over: EAST FORK SALMON RIVER

28 MILES UP EAST FORK R., Custer, ID

Built 1960 Load: 19.1 t ADT: 50

STC3830;W ID BLVD

Fair

Over: SEVEN MILE SLOUGH

0.1 SW. LETHA, Gem, ID

Built 1973 Load: 19.1 t ADT: 570

AILOR ROAD

Fair

Over: BIG BEAR CREEK;SW DEARY

0.4 S. 2.5 W. DEARY, Latah, ID

Built 1975 Load: 19.1 t ADT: 50

LITTLE BEAR ROAD

Fair

Over: BIG BEAR CREEK

1.5 N. 0.1 E. KENDRICK, Latah, ID

Built 1959 Load: 19.1 t ADT: 60

STC2781;4 MILE RD

Fair

Over: MILNER GOODING CANAL

4.3 N. 2.3 W. SHOSHONE, Lincoln, ID

Built 1965 Load: 19.1 t ADT: 880

SIBERTS OLD RIVER

Fair

Over: FISHHOOK CREEK

2.1 W. AVERY, Shoshone, ID

Built 1935 Load: 19.1 t ADT: 320

S5752;THOMPSON PAS

Fair

Over: BUTTE CREEK

0.9 S. 1.5 E. MURRAY, Shoshone, ID

Built 1977 Load: 19.1 t ADT: 230

FS ROUTE 509

Fair

Over: ST JOE RIVER

20 MI FROM AVERY, ID, Shoshone, ID

Built 1954 Load: 19.1 t ADT: 50

NO DATA ENTERED

Fair

Over: HAZARD CREEK

NO DATA ENTERED, Idaho, ID

Built 1963 Load: 19.4 t ADT: 50

NO DATA ENTERED

Fair

Over: SMITH CREEK

NO DATA ENTERED, Valley, ID

Built 1972 Load: 19.4 t ADT: 50

IRR BIA RTE 182

Fair

Over: BANNOCK CREEK

14 KM S JCT I-15 & RT 161, Power, ID

Built 1972 Load: 19.6 t ADT: 30

FDR

Fair

Over: SALMON RIVER

1 MILE SOUTH SMILEY CREEK, Blaine, ID

Built 1957 Load: 19.8 t ADT: 50

FDR

Fair

Over: ALTURAS LAKE CREEK

12 MILES SOUTH OF STANLEY, Custer, ID

Built 1955 Load: 19.8 t ADT: 50

FDR

Fair

Over: SALMON RIVER

4 MILES NE OF STANLEY, Custer, ID

Built 1969 Load: 19.8 t ADT: 50

Showing 251-300 of 1,742 bridges

Related

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Data sourced from the FHWA National Bridge Inventory (NBI), latest released cycle. See our methodology for details. Retrieved and formatted by PlainBridges Editorial.

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). A "structurally deficient" rating is a repair-priority signal, not a closure or unsafe-to-cross designation. Consult a qualified civil engineer before making decisions based on this data.

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.