US Bridges

County Road 304 over Pennel Creek 036

Fair

Custer County, Montana · 5M NW Ismay · Structure no. L09304005+06001

Built
1982
43 years old
Condition
Fair
inspected April 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
50 ft
1 main span
Daily traffic
18
2023 count
Owner
County
County Highway Agency

About this bridge

County Road 304 over Pennel Creek 036 is a steel stringer/multi-beam or girder carrying County Road 304 over Pennel Creek 036 in Custer County, Montana. It was built in 1982, so it is 43 years old, younger than the Montana average of 47 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 18 vehicles a day, roughly 3% of them trucks, projected to reach 19 by 2043. The structure is 50 ft (15.2 m) long and 24 ft wide. If it were closed, the detour would be 16.2 mi (26 km).

Location

Open in Google Maps
CarriesCounty Road 304
CrossesPennel Creek 036
Location5M NW Ismay
RouteCounty Highway 9304
CountyCuster County
StateMontana
Coordinates46.56793, -104.83752
Functional classRural Major Collector

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating47.8 US tons
Inventory rating37.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, precast panels
Main spans1
Design loadHS 20
Structure length50 ft (15.2 m)
Longest span47 ft (14.3 m)
Deck width24 ft (7.2 m)
Roadway width22 ft (6.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic18 (2023)
Projected traffic19 by 2043
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed16.2 mi (26 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was County Road 304 over Pennel Creek 036 built?

It was built in 1982, making it 43 years old in 2025.

What condition is County Road 304 over Pennel Creek 036 in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in April 2023.

How much traffic does County Road 304 over Pennel Creek 036 carry?

About 18 vehicles per day (2023 count), of which roughly 3% are trucks.

How long is County Road 304 over Pennel Creek 036?

The structure is 50 ft (15.2 m) long with a longest span of 47 ft (14.3 m) and a deck 24 ft wide.

Who owns County Road 304 over Pennel Creek 036?

It is owned by the County Highway Agency.