Bridge conditions in Cascade County, Montana
185 inventoried bridges · 11 rated poor · 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
The federal inventory lists 185 bridges in Cascade County: 77 rated good, 97 fair, and 11 poor.
- 11 of the 185 bridges in Cascade County, Montana, are rated in poor condition (5.9%) in the 2025 National Bridge Inventory, as of .
- 77 bridges (41.6%) are rated good and 97 (52.4%) fair.
- The median Cascade County bridge was built in 1966.
- The busiest poor-rated bridge is US 87 over Otter Creek (built 1959), carrying about 2,314 vehicles a day.
Good 41.6% · Fair 52.4% · Poor 5.9% of 185 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 |
|---|---|---|---|
| US 87 over Otter Creek | 1959 | 2,314 | Poor |
| US 87 over Otter Creek | 1959 | 2,314 | Poor |
| US 87 over Otter Creek | 1959 | 2,314 | Poor |
| Sun River Rd over Sep West Hill-i 15 127 | 1967 | 1,364 | Poor |
| US 89 Fh 32 over Belt Creek | 1968 | 833 | Poor |
| Old US 91 over Missouri River-rr 069 | 1931 | 316 | Poor |
| Old US Hwy 91 over Little Muddy Creek 090 | 1923 | 100 | Poor |
| Sheep CR Rd over Sheep Creek 097 | 1950 | 68 | Poor |
| Nfsr 487 over S Fk Judith River | 1958 | 65 | Poor |
| Fdr 267 over Jefferson Creek | 1957 | 50 | Poor |
| Nfsr 839 over Belt Creek | 1954 | 46 | Poor |
Busiest bridges in the county
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Central Ave over Missouri River-ped Trail | 1980 | 24,549 | Good |
| 15TH St N-us 87 over Missouri R-rivers Trail | 1962 | 14,369 | Fair |
| 9TH St N over Missouri River | 1996 | 14,024 | Fair |
| 6TH St SW over Sun River | 1980 | 13,800 | Fair |
| US 87-mt 3-mt 200 over Missouri River-u5205-rr | 1983 | 13,666 | Fair |
| US 89-mt 3-mt 200 over Missouri River-u5205-rr | 1951 | 13,666 | Fair |
| I 315S over Int I 15 | 1967 | 12,651 | Fair |
| Central Ave W over Int Central Ave W-i 15 | 1967 | 12,316 | Fair |
| I 315S over Fau 5225-14th St SW | 1967 | 6,326 | Good |
| I 315S over Fau 5225-14th St SW | 1967 | 6,326 | Good |
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.