Idaho bridges
Idaho reports 4,646 bridges and culverts across 44 counties. 250 (5.4%) are rated in poor condition, and 379 are posted with load limits or closed. The oldest structure still in the inventory dates from 1908.
Find a bridge in Idaho
Type at least two characters, or pick a condition or type, to search every bridge in the state.
Counties
Circle size reflects the number of bridges- Ada County 302
- Adams County 87
- Bannock County 128
- Bear Lake County 34
- Benewah County 48
- Bingham County 263
- Blaine County 96
- Boise County 89
- Bonner County 104
- Bonneville County 213
- Boundary County 84
- Butte County 32
- Camas County 62
- Canyon County 291
- Caribou County 45
- Cassia County 117
- Clark County 39
- Clearwater County 88
- Custer County 126
- Elmore County 98
- Franklin County 23
- Fremont County 138
- Gem County 57
- Gooding County 80
- Idaho County 216
- Jefferson County 125
- Jerome County 111
- Kootenai County 159
- Latah County 119
- Lemhi County 114
- Lewis County 21
- Lincoln County 53
- Madison County 80
- Minidoka County 67
- Nez Perce County 72
- Oneida County 23
- Owyhee County 49
- Payette County 65
- Power County 71
- Shoshone County 261
- Teton County 37
- Twin Falls County 126
- Valley County 153
- Washington County 80
Condition
Good32%(1,468)
Fair63%(2,928)
Poor5%(250)
Counties with the highest share of poor bridges
- Lincoln County26.4% of 53
- Boundary County13.1% of 84
- Clark County12.8% of 39
- Camas County11.3% of 62
- Custer County11.1% of 126
Structure types
| Structure type | Bridges | Share |
|---|---|---|
| Stringer/Multi-beam or Girder | 2,229 | 48.0% |
| Tee Beam | 884 | 19.0% |
| Frame | 639 | 13.8% |
| Box Beam or Girders - Multiple | 241 | 5.2% |
| Slab | 215 | 4.6% |
| Culvert | 156 | 3.4% |
| Truss - Thru | 80 | 1.7% |
| Box Beam or Girders - Single or Spread | 65 | 1.4% |
| Channel Beam | 50 | 1.1% |
| Girder and Floorbeam System | 50 | 1.1% |
| Arch - Deck | 20 | 0.4% |
| Truss - Deck | 8 | 0.2% |
| Arch - Thru | 3 | 0.1% |
| Suspension | 2 | 0.0% |
| Other | 2 | 0.0% |
| Movable - Lift | 1 | 0.0% |
| Segmental Box Girder | 1 | 0.0% |
When Idaho's bridges were built
Busiest
- I 84 Ebl & Wbl over Ridenbaugh CanalFairAda County · 144,500 vehicles/day
- I 84 over Ten Mile CreekFairAda County · 131,000 vehicles/day
- I 84 Wbl & Ebl over I 84B ;garrity Blvd IcGoodCanyon County · 111,000 vehicles/day
- I 84 Ebl & Wbl over Uprr;east Lateral CanalGoodCanyon County · 104,000 vehicles/day
- I 84 Ebl Wbl over Northside Blvd IcGoodCanyon County · 84,500 vehicles/day
Longest
- US 95 over Pend Oreille R;sandpointFairBonner County · 5,899 ft
- I 90 over I 90B;CANYON CRFairShoshone County · 4,478 ft
- SMA7344;BRYDEN Cyn over Snake R;high/Southway BrFairNez Perce County · 1,866 ft
- I 90 over Bennett Bay;sunnyside RDFairKootenai County · 1,730 ft
- SH 16 over Boise RiverGoodAda County · 1,726 ft
Oldest
- Wildhorse Road over Wildhorse RiverPoorAdams County · Built 1908
- Railroad Grade RD over St. Joe RiverFairBenewah County · Built 1908
- Sperry Grade RD over Potlatch Rvr(sperry Br)FairNez Perce County · Built 1908
- Stc 5711;MOON Pass over Big Dick CreekPoorShoshone County · Built 1909
- Stc 5711;MOON Pass over Squaw CreekFairShoshone County · Built 1909
Newest
- I 90 Wbl over SH 41GoodKootenai County · Built 2024
- I 90 Wbl over I 90 EB Off RampGoodKootenai County · Built 2024
- I 90 Wbl over I 90 EB on RampGoodKootenai County · Built 2024
- I 90 Wbl over SH 41GoodKootenai County · Built 2024
- I84 Ebl Wbl over B-4 CanalGoodMinidoka County · Built 2024
Who owns Idaho's bridges
| County | 1,571 | 33.8% |
| State | 1,386 | 29.8% |
| Federal | 729 | 15.7% |
| Local | 675 | 14.5% |
| City | 278 | 6.0% |
| Private | 4 | 0.1% |
| Unknown | 3 | 0.1% |
More Idaho facts
Total bridge length88 miles
Total deck area19,872,732 sq ft
Culverts counted as bridges156 (3%)
On the National Highway System845
Posted with load limits365
Closed to traffic14
Listed or eligible for the National Register4
Average daily traffic per bridge3,313 vehicles
Newest structure2024