Bridge conditions in Sweet Grass County, Montana
94 inventoried bridges · 6 rated poor · 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
6 of the 94 bridges the federal inventory lists in Sweet Grass County are rated poor; the rest split 30 good and 58 fair.
- 6 of the 94 bridges in Sweet Grass County, Montana, are rated in poor condition (6.4%) in the 2025 National Bridge Inventory, as of .
- 30 bridges (31.9%) are rated good and 58 (61.7%) fair.
- The median Sweet Grass County bridge was built in 1980.
- The busiest poor-rated bridge is S 91 over Boulder River Overflow (built 1937), carrying about 2,133 vehicles a day.
Good 31.9% · Fair 61.7% · Poor 6.4% of 94 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 91 over Boulder River Overflow | 1937 | 2,133 | Poor |
| US 191 over Rye Creek | 1947 | 661 | Poor |
| Bointer Rd over Sweet Grass Creek 044 | 1970 | 100 | Poor |
| Upper Deer CR Rd over Upper Deer Creek 028 | 1975 | 100 | Poor |
| Mcleod Main St over West Boulder River 025 | 1912 | 100 | Poor |
| Old US 10 over Work Creek 041 | 1932 | 29 | Poor |
Busiest bridges in the county
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I 90 over Spring Creek | 1980 | 12,306 | Fair |
| I 90 over Work Creek | 1972 | 10,845 | Fair |
| I 90 over Upper Deer Creek | 1980 | 6,153 | Fair |
| I 90 over Upper Deer Creek | 1980 | 6,153 | Fair |
| I 90 over Lower Deer Creek | 1980 | 6,153 | Fair |
| I 90 over Lower Deer Creek | 1980 | 6,153 | Good |
| I 90 over Int Springdale | 1981 | 6,090 | Good |
| I 90 over Int Springdale | 1981 | 6,090 | Good |
| I 90 over Jarrett CR Farm Access | 1981 | 6,090 | Fair |
| I 90 over Jarrett CR Farm Access | 1981 | 6,090 | 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.