US Bridges

Mn 73 over Sturgeon River

Fair

St. Louis County, Minnesota · 15.6 MI N of N JCT TH 16 · Structure no. 6554

Built
1948
77 years old
Condition
Fair
inspected June 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
109 ft
3 main spans
Daily traffic
556
2022 count
Owner
State
State Highway Agency

About this bridge

Mn 73 over Sturgeon River is a steel continuous stringer/multi-beam or girder carrying Mn 73 over Sturgeon River in St. Louis County, Minnesota. It was built in 1948, so it is 77 years old, older than the Minnesota average of 38.5 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.

It carries about 556 vehicles a day, roughly 16% of them trucks, projected to reach 680 by 2042. The structure is 109 ft (33.1 m) long and 39 ft wide. If it were closed, the detour would be 29.8 mi (48 km).

Location

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CarriesMn 73
CrossesSturgeon River
Location15.6 MI N of N JCT TH 16
RouteState Highway 73
CountySt. Louis County
StateMinnesota
Coordinates47.71019, -92.86505
Functional classRural Minor Arterial

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry7: Better than present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating77.6 US tons
Inventory rating46.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length109 ft (33.1 m)
Longest span43 ft (13.1 m)
Deck width39 ft (12 m)
Roadway width36 ft (11 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic556 (2022)
Projected traffic680 by 2042
Trucks16%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed29.8 mi (48 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState 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 Mn 73 over Sturgeon River built?

It was built in 1948, making it 77 years old in 2025.

What condition is Mn 73 over Sturgeon River 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 June 2023.

How much traffic does Mn 73 over Sturgeon River carry?

About 556 vehicles per day (2022 count), of which roughly 16% are trucks.

How long is Mn 73 over Sturgeon River?

The structure is 109 ft (33.1 m) long with a longest span of 43 ft (13.1 m) and a deck 39 ft wide.

Who owns Mn 73 over Sturgeon River?

It is owned by the State Highway Agency.