US Bridges

Milwaukee RD over Yellowstone River 030

FairPosted for load

Prairie County, Montana · 4M SW Terry · Structure no. L40042002+06001

Built
1907
118 years old
Condition
Fair
inspected July 2023
Type
Truss - Thru
Steel
Length
1,078 ft
4 main spans
Daily traffic
37
2023 count
Owner
County
County Highway Agency

About this bridge

Milwaukee RD over Yellowstone River 030 is a steel truss - thru carrying Milwaukee RD over Yellowstone River 030 in Prairie County, Montana. It was built in 1907, so it is 118 years old, older 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 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. Its operating status is: posted for load restriction.

It carries about 37 vehicles a day, roughly 3% of them trucks, projected to reach 39 by 2043. The structure is 1,078 ft (328.5 m) long and 10 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

Open in Google Maps
CarriesMilwaukee RD
CrossesYellowstone River 030
Location4M SW Terry
RouteCounty Highway 42
CountyPrairie County
StateMontana
Coordinates46.77922, -105.412
Functional classRural Local

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating31 US tons
Inventory rating23 US tons

Structure

Structure typeTruss - Thru
MaterialSteel
DeckWood or timber
Main spans4
Design loadHS 20
Structure length1,078 ft (328.5 m)
Longest span269 ft (82.1 m)
Deck width10 ft (3 m)
Roadway width9 ft (2.8 m)
Vertical clearance over deck24 ft (7.2 m)

Traffic and service

Average daily traffic37 (2023)
Projected traffic39 by 2043
Trucks3%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed123.7 mi (199 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$1.3 million
NavigationNo navigation control on waterway

Frequently asked questions

When was Milwaukee RD over Yellowstone River 030 built?

It was built in 1907, making it 118 years old in 2025.

What condition is Milwaukee RD over Yellowstone River 030 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 July 2023.

How much traffic does Milwaukee RD over Yellowstone River 030 carry?

About 37 vehicles per day (2023 count), of which roughly 3% are trucks.

How long is Milwaukee RD over Yellowstone River 030?

The structure is 1,078 ft (328.5 m) long with a longest span of 269 ft (82.1 m) and a deck 10 ft wide.

Who owns Milwaukee RD over Yellowstone River 030?

It is owned by the County Highway Agency.