Forest Grove Rd over S Fork Mcdonald CR
Fergus County, Montana · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Forest Grove Rd over S Fork Mcdonald CR in Fergus County, Montana, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 8 (very good condition) on the 0-9 scale.
- It was built in 2021, making it 4 years old at the 2025 inventory.
- It carries about 120 vehicles a day (traffic count year 2023).
- Its listed owner is the county highway agency.
- It is one of 52 of the 158 inventoried bridges in Fergus County rated good (32.9%); 9 (5.7%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated January 2025, on a 24-month routine inspection cycle.
- A good rating means every major component - deck, superstructure, substructure, or culvert - is rated 7 or higher on FHWA's 0-9 scale: no more than minor problems.
View this bridge on a map → (46.98743, -108.91598)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 8 | 8 | Very good condition |
| Superstructure | 8 | 8 | Very good condition |
| Substructure | 8 | 8 | Very good condition |
Bridge details
| Structure | Prestressed concrete stringer or multi-beam girder |
| Length | about 64 ft |
| Location | 6M SW Grassrange |
| NBI structure number | 000000202102773 |
| Condition class | Good |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | January 2025 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 5: foundations stable, scour within the limits of the footing or piles |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Montana department of transportation.
Busiest bridges in Fergus County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US 87-e Main St over Mill Ditch | 1922 | 8,747 | Fair |
| US 87-w Main St over Big Spring Creek | 1962 | 5,357 | Fair |
| US 191-1st Ave N over Big Spring Creek | 1960 | 5,189 | Fair |
| US 87 over Boyd Creek | 1942 | 2,831 | Fair |
| US 191-kendall Rd over Big Spring Creek | 1976 | 2,663 | Fair |
| US 87 over Beaver Creek | 2009 | 2,589 | Good |
All bridges nearby: Fergus County, MT bridge conditions · every bridge in Fergus County · Montana bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.