Bridge conditions in Custer County, Idaho
126 inventoried bridges · 14 rated poor · 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
Of the 126 Custer County bridges in the federal inventory, 14 carry a poor rating. That 11.1% share is roughly 2x the national average.
- 14 of the 126 bridges in Custer County, Idaho, are rated in poor condition (11.1%) in the 2025 National Bridge Inventory, as of .
- 40 bridges (31.7%) are rated good and 72 (57.1%) fair.
- The median Custer County bridge was built in 1972.
- The busiest poor-rated bridge is SH 75 over Yankee Fk of Salmon Rivr (built 1934), carrying about 680 vehicles a day.
Good 31.7% · Fair 57.1% · Poor 11.1% of 126 bridges
Bridges rated poor
Every bridge in the county with a poor rating, busiest first. Poor means a major component is rated 4 or lower on FHWA's 0-9 scale; it is a repair flag, not a closure notice.
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| SH 75 over Yankee Fk of Salmon Rivr | 1934 | 680 | Poor |
| Squaw Creek Road over Squaw Creek | 1960 | 330 | Poor |
| Squaw Creek Rd over Squaw Creek | 1960 | 330 | Poor |
| Squaw Creek Rd over Squaw Creek | 1960 | 300 | Poor |
| Squaw Creek Rd over Squaw Creek | 1960 | 100 | Poor |
| Custer Motorway over Yankee Fork | 1992 | 100 | Poor |
| Beaver-loon Road over Jordan Creek | 1993 | 100 | Poor |
| Beaver-loon Road over Jordan Creek | 1957 | 100 | Poor |
| East Fork Rd over Road Creek | 2022 | 90 | Poor |
| Old Chilli Road over Thousand Springs Creek | 1926 | 80 | Poor |
| Mule Shoe Mine Rd over Salmon River;se.clayton | 1930 | 60 | Poor |
| No Data Entered over No Data Entered | 1972 | 50 | Poor |
| Fdr over Pettit Lake Creek | 1982 | 50 | Poor |
| Fdr over Valley Creek | 1950 | 50 | Poor |
Busiest bridges in the county
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US 93 over Garden Creek | 1941 | 2,300 | Fair |
| SH 21 over Crooked Creek | 1968 | 2,200 | Fair |
| US 93 over Big Lost River | 1987 | 1,500 | Fair |
| US 93 over Challis Creek | 1991 | 1,400 | Good |
| US 93 over Salmon River;challis Br. | 1995 | 1,400 | Good |
| Capitol Avenue over Swauger Slough | 1940 | 1,220 | Fair |
| SH 75 over Redfish Lake Creek | 1960 | 1,100 | Fair |
| SH 75 over Salmon River | 1954 | 1,100 | Fair |
| SH 75 over Gini Canal | 1988 | 1,100 | Good |
| US 93 over Salmon River (watts Br.) | 2009 | 1,100 | Good |
Source: FHWA National Bridge Inventory, 2025. Counts cover inventoried highway bridges over 20 feet; ratings are reported by the state DOT.
All of Idaho: Idaho bridge conditions by county · every download on the data page.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.