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

N YELLOWSTONE HWY

Fair

Over: DRY BED CANAL

1.8 N. 1.2 E. RIGBY, Jefferson, ID

Built 1999 Load: 71.7 t ADT: 3,400

ALPINE STEET

Fair

Over: ELEC LGHT SWITCH LATERAL

IN BOISE, Ada, ID

Built 1970 Load: 73.5 t ADT: 960

N 3700 E ROAD

Fair

Over: PERRINE COULEE CANAL

1.3 W. 1.3 S. HANSEN, Twin Falls, ID

Built 1962 Load: 76.2 t ADT: 70

SMA 9183;TEN MILE

Fair

Over: RIDENBAUGH CANAL

0.3 S. OVERLAND-TEN MILE, Ada, ID

Built 1993 Load: 78.9 t ADT: 18,500

RAILROAD GRADE RD

Fair

Over: ST. JOE RIVER

16.0 E. ST. MARIES, Benewah, ID

Built 1908 Load: 78.9 t ADT: 40

STC6732;OLD HWY 91

Fair

Over: CAMAS CREEK

4.3 N. 1.0 W. HAMER, Jefferson, ID

Built 2001 Load: 80.7 t ADT: 280

E. STAGE COACH RD

Fair

Over: MORA CANAL

4.5 N. 0.5 W. MELBA, Canyon, ID

Built 2004 Load: 84.4 t ADT: 200

W 1000 S

Fair

Over: BIG COTTONWOOD CREEK

5.4 W. 6.5 S. PELLA, Cassia, ID

Built 1970 Load: 89.8 t ADT: 670

SH 3

Fair

Over: THORN CREEK

4.5 S. ST MARIES, Benewah, ID

Built 1939 Load: 91.6 t ADT: 2,200

STP 3794;EAGLE RD

Fair

Over: FARR LATERAL CANAL

3.4 N. 3.3 E. KUNA, Ada, ID

Built 1993 Load: 99.9 t ADT: 1,900

STC 1829; PARKS RD

Fair

Over: DRAIN DITCH

0.3 S. 1.2 W. MORELAND, Bingham, ID

Built 1989 Load: 99.9 t ADT: 970

SH 162

Fair

Over: SEVEN MILE CREEK

4.4 S. KAMIAH, Idaho, ID

Built 1997 Load: 99.9 t ADT: 1,100

I 90 EBL & WBL

Fair

Over: CEDAR CREEK

11.6 E. COEUR D'ALENE, Kootenai, ID

Built 1988 Load: 99.9 t ADT: 14,500

US 95

Fair

Over: E.FK. LAPWAI CREEK

4.9 N. 1.0 E. WINCHESTER, Lewis, ID

Built 1957 Load: 99.9 t ADT: 3,500

SH 78

Fair

Over: REYNOLDS CREEK

16.4 E. MARSING, Owyhee, ID

Built 1954 Load: 99.9 t ADT: 790

STC 1753;ARBON VLY

Fair

Over: BANNOCK CR.;S.PAULINE BR

0.5 S. PAULINE, Power, ID

Built 1962 Load: 99.9 t ADT: 110

NO DATA ENTERED

Good

Over: W.F. EMERALD

NO DATA ENTERED, Benewah, ID

Built 2020 ADT: 50

FDR

Good

Over: POLE CREEK

2 MILES UP POLE CREEK ROD, Blaine, ID

Built 2013 ADT: 50

NO DATA ENTERED

Good

Over: ROARING RIVER

NO DATA ENTERED, Boise, ID

Built 2007 ADT: 50

NO DATA ENTERED

Good

Over: SCRIVER CREEK

NO DATA ENTERED, Boise, ID

Built 2022 ADT: 50

FS ROUTE NO. 419

Good

Over: RATTLE CREEK

RATTLE CREEK, Bonner, ID

Built 1953 ADT: 50

FS ROUTE NO. 628

Good

Over: E.F. BOULDER

EAST FORK BOULDER, Boundary, ID

Built 2022 ADT: 50

FDR 40135

Good

Over: ANTELOPE CREEK

ANTELOPE G.S., Butte, ID

Built 2007 ADT: 20

ROAD

Good

Over: EAST CAMAS CREEK

NO DATA ENTERED, Clark, ID

Built 1995 ADT: 50

FDR 555

Good

Over: WEITAS CREEK

WEITAS GUARD STATION, Clearwater, ID

Built 1985 ADT: 10

FDR 382

Good

Over: ELK CREEK

8 MILES FROM ELK RIVER ID, Clearwater, ID

Built 2021 ADT: 10

FDR

Good

Over: EAST FORK SALMON RIVER

20 MILES FROM MOUTH OF R., Custer, ID

Built 1989 ADT: 50

FDR

Good

Over: EAST FORK SALMON RIVER

BOWERY GUARD STATION, Custer, ID

Built 1991 ADT: 50

FDR

Good

Over: HUCKELBERRY CREEK

3 MILES WEST SESSIONS LOE, Custer, ID

Built 1984 ADT: 50

FDR

Good

Over: VALLEY CREEK

NORTH MP120.7 ST HWY 21, Custer, ID

Built 1986 ADT: 60

FDR

Good

Over: IRON CREEK

1.2 MILES UP FROM HWY 21, Custer, ID

Built 2012 ADT: 50

FDR

Good

Over: WILLOW CREEK

2 MILES EAST SHAKE CR G S, Elmore, ID

Built 1955 ADT: 50

ROAD

Good

Over: WARM RIVER

NO DATA ENTERED, Fremont, ID

Built 2010 ADT: 50

FSR 360

Good

Over: HORSE CREEK

NEAR ELK SUMMIT CG, Idaho, ID

Built 2009 ADT: 50

NO DATA ENTERED

Good

Over: SUMMIT CREEK

NO DATA ENTERED, Idaho, ID

Built 1977 ADT: 50

FDR 377D

Good

Over: W FK POTLATCH CREEK

2 MI WEST OF ST HWY, Latah, ID

Built 1981 ADT: 5

DEEP CR. ROAD

Good

Over: DEEP CREEK

14 miles SW of Salmon, ID, Lemhi, ID

Built 2008 ADT: 100

SHEEP CR. ROAD

Good

Over: SHEEP CREEK

NO DATA ENTERED, Lemhi, ID

Built 1985 ADT: 50

NO DATA ENTERED

Good

Over: SILVER CREEK

NO DATA ENTERED, Valley, ID

Built 2009 ADT: 10

NO DATA ENTERED

Good

Over: FOUR MILE CK

NO DATA ENTERED, Valley, ID

Built 1999 ADT: 50

NO DATA ENTERED

Good

Over: NO DATA ENTERED

NO DATA ENTERED, Valley, ID

Built 2023 ADT: 50

MANN CK RD 50009

Good

Over: 4TH OF JULY CREEK

NO DATA ENTERED, Washington, ID

Built 2008 ADT: 50

NO DATA ENTERED

Good

Over: PANTHER CREEK

NO DATA ENTERED, Lemhi, ID

Built 1981 Load: 9.4 t ADT: 50

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

Showing 1,051-1,100 of 1,742 bridges

Related

All states → | National rankings → | Understanding conditions → | SD bridges explained →
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.