Bridge conditions in Mineral County, Montana
153 inventoried bridges · 17 rated poor · 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
Of the 153 Mineral County bridges in the federal inventory, 17 carry a poor rating. That 11.1% share is roughly 2x the national average.
- 17 of the 153 bridges in Mineral County, Montana, are rated in poor condition (11.1%) in the 2025 National Bridge Inventory, as of .
- 37 bridges (24.2%) are rated good and 99 (64.7%) fair.
- The median Mineral County bridge was built in 1973.
- The busiest poor-rated bridge is I 90 over Sep Elizabeth Ln (built 1965), carrying about 4,088 vehicles a day.
Good 24.2% · Fair 64.7% · Poor 11.1% of 153 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 |
|---|---|---|---|
| I 90 over Sep Elizabeth Ln | 1965 | 4,088 | Poor |
| I 90 over Clark Fork River | 1965 | 4,088 | Poor |
| I 90 over Clark Fork River | 1984 | 3,719 | Poor |
| Old Hwy 10 W over Clark Fork 054 | 1932 | 356 | Poor |
| S Frontage Rd W over Clark Fork 053 | 1916 | 174 | Poor |
| Old Hwy 10 E over St Regis River 059 | 1937 | 140 | Poor |
| Mullan Rd E over Nemote Creek 006 | 1931 | 100 | Poor |
| Sloway Frntge Rd E over Abandoned RR 001 | 1956 | 100 | Poor |
| No Data Entered over S Fk Fish Creek | 1973 | 50 | Poor |
| Rd 343-2 over S Fk Fish Creek | 1966 | 50 | Poor |
| Fish CR Rd over S Fk Fish Creek | 1965 | 50 | Poor |
| Fish CR Rd over W Fk Fish Creek | 1966 | 50 | Poor |
| Rd 320 over Cedar CR | 1959 | 50 | Poor |
| Rd 352 over Twelvemile Creek | 1955 | 50 | Poor |
| Rd 352 over Twelvemile Creek | 1955 | 50 | Poor |
| Rd 388 over Cedar CR | 1954 | 50 | Poor |
| No Data Entered over Henderson Creek | 1955 | 40 | Poor |
Busiest bridges in the county
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I 90 over Drainage | 1986 | 8,111 | Good |
| I 90 over Sep Local Road | 1973 | 7,824 | Fair |
| I 90 over Sep Local Road | 1973 | 7,824 | Fair |
| I 90 over Int Taft | 1973 | 7,824 | Fair |
| I 90 over Sep Randolph Creek Road | 1973 | 7,824 | Fair |
| I 90 over St. Regis River | 1973 | 7,824 | Fair |
| I 90 over Int Lozeau County Road | 1967 | 7,649 | Good |
| I 90 over Int Saltese | 1973 | 7,448 | Fair |
| I 90 over St. Regis River | 1973 | 7,448 | Fair |
| I 90 over Int Henderson | 1980 | 7,448 | Fair |
Source: FHWA National Bridge Inventory, 2025. Counts cover inventoried highway bridges over 20 feet; ratings are reported by the state DOT.
All of Montana: Montana 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.