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

NFSR 50172

Good

Over: E FK WEISER RIVER

NO DATA ENTERED, Adams, ID

Built 2013 Load: 28.5 t ADT: 50

WILLOW CK.-CRKD.R.

Good

Over: CROOKED RIVER

7 MI NW DEER PARK, Boise, ID

Built 1970 Load: 28.5 t ADT: 5

LT. ANDERSON CK RD

Good

Over: ANDERSON CREEK

2 MI NE OF GARDEN VALLEY, Boise, ID

Built 1983 Load: 28.5 t ADT: 12

CANAL ROAD

Good

Over: SAND CREEK CHANNEL

RIRIE DAM, Bonneville, ID

Built 1976 Load: 28.5 t ADT: 3

CANAL ROAD

Good

Over: RIRIE OUTLET CH WILLW CR

RIRIE OUTLET CHANNEL, Bonneville, ID

Built 1976 Load: 28.5 t ADT: 3

FOREST ROAD 642

Good

Over: SO. FK. WHITE BIRD CREEK

NO DATA ENTERED, Idaho, ID

Built 2008 Load: 28.5 t ADT: 25

IRON CREEK ROAD

Good

Over: IRON CREEK

20 S. 4 W. SALMON, Lemhi, ID

Built 2010 Load: 28.5 t ADT: 50

3708: DEEP CREEK

Good

Over: Deep Creek

47.1 mi S of ID78, Owyhee, ID

Built 1983 Load: 28.5 t ADT: 25

FS ROUTE NO. 638

Good

Over: GRANITE CREEK

GRANITE CREEK, Bonner, ID

Built 2010 Load: 28.8 t ADT: 50

FS ROUTE NO. 1341

Good

Over: NO DATA ENTERED

BOTTOM CREEK, Kootenai, ID

Built 2007 Load: 28.8 t ADT: 40

STORMY PEAK ROAD

Good

Over: EAST BOULDER CREEK

NO DATA ENTERED, Lemhi, ID

Built 1983 Load: 28.8 t ADT: 50

SH 21

Good

Over: BOISE RIVER

NEAR DIVERSION DAM, Ada, ID

Built 1996 Load: 29.0 t ADT: 6,400

SMA 7343;CHERRY LN

Good

Over: TEN MILE CREEK

0.5 N. 3.5 W. MERIDIAN, Ada, ID

Built 1961 Load: 29.0 t ADT: 5,900

W ANTELOPE;FR 137

Good

Over: ANTELOPE CREEK

1.0 S. 21.6 W. ARCO, Butte, ID

Built 1966 Load: 29.0 t ADT: 10

N 2300 E

Good

Over: S. BRANCH WILFORD CANAL

1.0 W. WILFORD, Fremont, ID

Built 1997 Load: 29.0 t ADT: 140

W HARBOR DRIVE

Good

Over: CHANNEL OF SPOKANE RIVER

1.4 S. 2.6 E. POST FALLS, Kootenai, ID

Built 2000 Load: 29.0 t ADT: 500

NO DATA ENTERED

Good

Over: HOODOO CREEK

ELK SUMMIT-RD 111, Idaho, ID

Built 1950 Load: 29.2 t ADT: 30

FOREST ROAD 1172

Good

Over: RED RIVER

NO DATA ENTERED, Idaho, ID

Built 1961 Load: 29.2 t ADT: 40

LEVEL C ROAD

Good

Over: E. FORK HAYDEN CREEK

NO DATA ENTERED, Lemhi, ID

Built 1974 Load: 29.2 t ADT: 10

FS ROUTE NO. 400

Good

Over: FLAT CREEK

19.1 MI FROM BABINS JCT., Shoshone, ID

Built 1976 Load: 29.2 t ADT: 40

FS ROAD 5112

Good

Over: LOLO CREEK

BRADFORD BRIDGE, Clearwater, ID

Built 2010 Load: 29.5 t ADT: 10

OLD CHILLY RD

Good

Over: BIG LOST RIVER

9.6 N 12.7 W MACKAY, Custer, ID

Built 2023 Load: 29.5 t ADT: 40

NO DATA ENTERED

Good

Over: LAKE CREEK

NO DATA ENTERED, Idaho, ID

Built 2001 Load: 29.5 t ADT: 50

CLEAR CREEK ROAD

Good

Over: M. FORK PAYETTE RIVER

14 MI SW OF WARM LAKE, Valley, ID

Built 1963 Load: 29.5 t ADT: 12

FS ROUTE NO. 2567

Good

Over: BEAVER CREEK

BEAVER CREEK, Boundary, ID

Built 1979 Load: 29.8 t ADT: 50

1920: DARLING CREE

Good

Over: Challis Creek

0.3 mi N of Challis Cr Rd, Custer, ID

Built 1981 Load: 29.8 t ADT: 25

FOREST ROAD 492

Good

Over: SO FK CLEARWATER RV

SANTIAM, Idaho, ID

Built 1980 Load: 29.8 t ADT: 50

Dam Crest Road

Good

Over: ANDERSON RANCH DAM SPWY

ANDERSON RANCH DAM, Elmore, ID

Built 1950 Load: 29.9 t ADT: 50

STC 3904;WARM LK

Good

Over: S.FK.SALMON RIVER

9.4 N. 16.8 E. CASCADE, Valley, ID

Built 1960 Load: 29.9 t ADT: 370

SMA 9793; MAIN ST

Good

Over: BOISE VRT CENTER

MAIN ST EAST OF 8TH ST, Ada, ID

Built 2016 Load: 30.1 t ADT: 6,000

FDR

Good

Over: HYNDMAN CREEK

8 MILES EAST OF KETCHUM, Blaine, ID

Built 1985 Load: 30.1 t ADT: 30

FS ROUTE NO. 1309

Good

Over: MYRTLE CREEK

MYRTLE CREEK, Boundary, ID

Built 1981 Load: 30.1 t ADT: 50

SANDS CANYON RD

Good

Over: LITTLE LOST RIVER

NO DATA ENTERED, Custer, ID

Built 1987 Load: 30.1 t ADT: 5

MIDDLE FK PAYETTE

Good

Over: RATTLESNAKE CREEK

.2 MI N RATTLESNAKE CK CG, Valley, ID

Built 2009 Load: 30.1 t ADT: 50

FS ROUTE NO. 435

Good

Over: KENO CREEK

KENO CREEK, Boundary, ID

Built 2011 Load: 30.5 t ADT: 40

FS ROUTE #2646

Good

Over: SNOW CREEK

10 MI. FROM BONNERS FERRY, Boundary, ID

Built 1980 Load: 30.5 t ADT: 40

NO DATA ENTERED

Good

Over: RAWHIDE CREEK

22 MI FROM KELLY FORKS WC, Clearwater, ID

Built 2010 Load: 30.5 t ADT: 100

FDR382

Good

Over: ELK CREEK

8 MILES FROM ELK RIVER, Clearwater, ID

Built 2017 Load: 30.5 t ADT: 20

1979: OLD STAGE

Good

Over: Morgan Creek

5 mi N of US93, Custer, ID

Built 2004 Load: 30.5 t ADT: 25

FS ROUTE NO.760

Good

Over: LITTLE LOST LAKE CREEK

LITTLE LOST LAKE, Shoshone, ID

Built 2006 Load: 30.5 t ADT: 40

STP 7073;COLE RD

Good

Over: RIDENBAUGH CANAL;COLE GS

0.7 W. BOISE WCL;COLE RD, Ada, ID

Built 1968 Load: 30.8 t ADT: 14,000

I 15 SBL

Good

Over: GIBSON CANAL

5.5 S. BLACKFOOT, Bingham, ID

Built 1959 Load: 30.8 t ADT: 13,000

SH 39

Good

Over: HIGHLINE CANAL

8.9 N. ABERDEEN, Bingham, ID

Built 1977 Load: 30.8 t ADT: 970

TWENTY MILE CR RD

Good

Over: TWENTY MILE CREEK

7.0 S 3.0 W BONNERS FERR, Boundary, ID

Built 2007 Load: 30.8 t ADT: 130

FDR 60055

Good

Over: NAPIAS CREEK

3 MILES N. OF COBALT ID, Lemhi, ID

Built 1974 Load: 30.8 t ADT: 50

NO DATA ENTERED

Good

Over: QUARTZ CREEK

N FK CLW RD 247, Clearwater, ID

Built 1965 Load: 31.1 t ADT: 120

NO DATA ENTERED

Good

Over: FIX CREEK

9 MI FROM KELLY FORKS WC, Clearwater, ID

Built 2010 Load: 31.1 t ADT: 50

FS ROUTE NO. 396

Good

Over: MARBLE CREEK

MARBLE CREEK, Shoshone, ID

Built 1986 Load: 31.1 t ADT: 50

LICK CREEK ROAD

Good

Over: LICK CREEK #2

13.2 NE MCCALL, Valley, ID

Built 2011 Load: 31.1 t ADT: 40

MCCOY CREEK RD

Good

Over: IOWA CREEK

NO DATA ENTERED, Bonneville, ID

Built 1985 Load: 31.4 t ADT: 36

Showing 1,251-1,300 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.