US Bridges

Ismay RD over Cottonwood Creek

Good

Fallon County, Montana · 3.9M S Ismay · Structure no. 000000202206646

Built
2023
2 years old
Condition
Good
inspected July 2023
Type
Culvert
Concrete
Length
48 ft
4 main spans
Daily traffic
38
2023 count
Owner
County
County Highway Agency

About this bridge

Ismay RD over Cottonwood Creek is a concrete culvert carrying Ismay RD over Cottonwood Creek in Fallon County, Montana. It was built in 2023, so it is 2 years old, younger than the Montana average of 47 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 38 vehicles a day, roughly 13% of them trucks, projected to reach 40 by 2043. The structure is 48 ft (14.6 m) long. If it were closed, the detour would be 24.9 mi (40 km).

CarriesIsmay RD
CrossesCottonwood Creek
Location3.9M S Ismay
RouteCounty Highway 320
StateMontana
Coordinates46.4566, -104.7886
Functional classRural Major Collector

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Channel and channel protection7 GoodSome minor problems.
Culvert8 Very GoodNo problems noted.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation8: Equal to present desirable criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating107.1 US tons
Inventory rating102.5 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans4
Design loadHL 93
Structure length48 ft (14.6 m)
Longest span12 ft (3.7 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic38 (2023)
Projected traffic40 by 2043
Trucks13%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed24.9 mi (40 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 Ismay RD over Cottonwood Creek built?

It was built in 2023, making it 2 years old in 2025.

What condition is Ismay RD over Cottonwood Creek in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in July 2023.

How much traffic does Ismay RD over Cottonwood Creek carry?

About 38 vehicles per day (2023 count), of which roughly 13% are trucks.

How long is Ismay RD over Cottonwood Creek?

The structure is 48 ft (14.6 m) long with a longest span of 12 ft (3.7 m).

Who owns Ismay RD over Cottonwood Creek?

It is owned by the County Highway Agency.