Bridge conditions in Stillwater County, Montana
92 inventoried bridges · 1 rated poor · 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
1 of the 92 bridges the federal inventory lists in Stillwater County are rated poor; the rest split 28 good and 63 fair.
- 1 of the 92 bridges in Stillwater County, Montana, are rated in poor condition (1.1%) in the 2025 National Bridge Inventory, as of .
- 28 bridges (30.4%) are rated good and 63 (68.5%) fair.
- The median Stillwater County bridge was built in 1971.
- The busiest poor-rated bridge is S 78 over Yellowstone River (built 1957), carrying about 5,017 vehicles a day.
Good 30.4% · Fair 68.5% · Poor 1.1% of 92 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 |
|---|---|---|---|
| S 78 over Yellowstone River | 1957 | 5,017 | Poor |
Busiest bridges in the county
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I 90 over Cove Irrigation Ditch | 1970 | 12,321 | Good |
| I 90 over Int Exit 396 | 1963 | 10,845 | Fair |
| I 90 over Int Park City | 1967 | 7,580 | Fair |
| I 90 over Int Park City | 1967 | 7,580 | Fair |
| I 90 over Sep Pope Road | 1967 | 7,580 | Fair |
| I 90 over Sep Pope Road | 1967 | 7,580 | Fair |
| I 90 over Int Columbus-9th St N | 1971 | 6,161 | Fair |
| I 90 over Int Columbus-9th St N | 1971 | 6,161 | Fair |
| I 90 over Hensley Cr-hensley CR Rd | 1970 | 6,161 | Fair |
| I 90 over Hensley Cr-hensley CR Rd | 1970 | 6,161 | 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.