I 90 over Antelope Creek
PoorGranite County, Montana · 11.2M W Drummond · Structure no. I00090142+08784
- Built
- 1971
- 54 years old
- Condition
- Poor
- inspected August 2023
- Type
- Stringer/Multi-beam or Girder
- Wood or Timber
- Length
- 43 ft
- 2 main spans
- Daily traffic
- 100
- 2025 count
- Owner
- State
- State Highway Agency
About this bridge
I 90 over Antelope Creek is a wood or timber stringer/multi-beam or girder carrying I 90 over Antelope Creek in Granite County, Montana. It was built in 1971, so it is 54 years old, older than the Montana average of 47 years.
The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.
It carries about 100 vehicles a day, roughly 3% of them trucks, projected to reach 100 by 2040. The structure is 43 ft (13.1 m) long and 20 ft wide. If it were closed, the detour would be 1.2 mi (2 km).
Location
Open in Google MapsCondition and inspection
The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 7 Good | Some minor problems. |
| Superstructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Substructure | 4 Poor | Advanced section loss, deterioration, spalling or scour. |
| Channel and channel protection | 8 Very Good | No problems noted. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was I 90 over Antelope Creek built?
It was built in 1971, making it 54 years old in 2025.
What condition is I 90 over Antelope Creek in?
The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in August 2023.
How much traffic does I 90 over Antelope Creek carry?
About 100 vehicles per day (2025 count), of which roughly 3% are trucks.
How long is I 90 over Antelope Creek?
The structure is 43 ft (13.1 m) long with a longest span of 21 ft (6.4 m) and a deck 20 ft wide.
Who owns I 90 over Antelope Creek?
It is owned by the State Highway Agency.