Lemhi County Bridge Report Card
Lemhi County scores 60 out of 100 on BridgeLookup's Bridge Condition Exposure Score, based on FHWA National Bridge Inventory records.
Lemhi County, Idaho
Lemhi County has 113 bridges in the National Bridge Inventory, with 9 rated poor and 5 rated scour-critical. Its poor-condition share of 8.0% is above the 5.4% statewide average. Poor-condition bridges carry about 8,495 daily vehicle crossings.
Quote-Ready Local Facts
Copyable Facts for Reporters
BridgeLookup.com gives Lemhi County a Bridge Condition Exposure Score of 60/100 (D). The county has 113 bridges in the National Bridge Inventory, including 9 in poor condition and 5 rated scour-critical. Poor-condition bridges carry about 8,495 daily vehicle crossings. Poor condition does not mean unsafe; bridges judged unsafe are closed or restricted by transportation agencies.
How the Score Breaks Down
| Factor | Weight | County Value | Penalty |
|---|---|---|---|
| Poor-condition bridge share | 40 | 8.0% | 15.9 |
| Poor-condition traffic exposure | 25 | 21.0% of measured traffic | 15.7 |
| Scour-critical bridge share | 20 | 4.4% | 8.8 |
| Average age vs national baseline | 10 | 37 years vs 48 nationally | 0.0 |
| Traffic-data completeness | 5 | 40,541 measured daily crossings | 0.0 |
Score = 100 minus weighted penalties. The score is a comparative research signal, not an official safety rating. Read the full methodology.
County Comparisons
| County Poor-Condition Share | 8.0% |
| State Poor-Condition Share | 5.4% |
| National Poor-Condition Share | 6.7% |
| County Scour-Critical Share | 4.4% |
| Average Bridge Age | 37 years |
| Poor-Condition Traffic Exposure | 8,495 vehicles/day |
Bridges to Watch
Top Bridges to Watch in Lemhi County
| Bridge | Reason | Condition | Daily Traffic | Year Built |
|---|---|---|---|---|
| US 93 over Salmon River;salmon Br. | Poor condition + traffic exposure | Poor | 7,300 | 1926 |
| Salmon River Road over Pine Creek | Poor condition + traffic exposure | Poor | 350 | 2012 |
| N. St. Charles over Lemhi River | Poor condition + traffic exposure | Poor | 310 | 1948 |
| No Data Entered over Boulder Creek | Poor condition + traffic exposure | Poor | 200 | 1966 |
| No Data Entered over Panther Creek | Poor condition + traffic exposure | Poor | 200 | 1980 |
| No Data Entered over Yellowjacket Creek | Poor condition + traffic exposure | Poor | 50 | 1962 |
| Viola Lane over Lemhi River(bagley Br) | Poor condition + traffic exposure | Poor | 50 | 1991 |
| Moccasin-napias RD over Napias Creek | Poor condition + traffic exposure | Poor | 25 | 1953 |
| Road over Bear Valley Creek | Poor condition + traffic exposure | Poor | 10 | 1960 |
| Idfg Access Road over Salmon River | Scour-critical foundation rating | Fair | 30 | 1989 |
Important safety note
Poor condition does not mean a bridge is unsafe. It means at least one major component has significant deterioration and the bridge is a priority for maintenance, repair, or replacement. Bridges judged unsafe are closed or restricted by transportation agencies.