US Bridges

Mn 70 over ST Croix River

Fair

Pine County, Minnesota · At Wisc ST Line · Structure no. 58004

Built
1991
34 years old
Condition
Fair
inspected September 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
605 ft
6 main spans
Daily traffic
3,901
2022 count
Owner
State
State Highway Agency

About this bridge

Mn 70 over ST Croix River is a steel continuous stringer/multi-beam or girder carrying Mn 70 over ST Croix River in Pine County, Minnesota. It was built in 1991, so it is 34 years old, younger 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 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 3,901 vehicles a day, roughly 7% of them trucks, projected to reach 4,250 by 2042. The structure is 605 ft (184.5 m) long and 48 ft wide. If it were closed, the detour would be 49.7 mi (80 km).

Location

Open in Google Maps
CarriesMn 70
CrossesST Croix River
LocationAt Wisc ST Line
RouteState Highway 70
CountyPine County
StateMinnesota
Coordinates45.77336, -92.78149
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
Deck8 Very GoodNo problems noted.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
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 alignment8: Equal to present desirable criteria
Operating rating83.9 US tons
Inventory rating50.2 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans6
Design loadHS 20
Structure length605 ft (184.5 m)
Longest span107 ft (32.6 m)
Deck width48 ft (14.5 m)
Roadway width39 ft (11.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,901 (2022)
Projected traffic4,250 by 2042
Trucks7%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed49.7 mi (80 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 70 over ST Croix River built?

It was built in 1991, making it 34 years old in 2025.

What condition is Mn 70 over ST Croix 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 September 2024.

How much traffic does Mn 70 over ST Croix River carry?

About 3,901 vehicles per day (2022 count), of which roughly 7% are trucks.

How long is Mn 70 over ST Croix River?

The structure is 605 ft (184.5 m) long with a longest span of 107 ft (32.6 m) and a deck 48 ft wide.

Who owns Mn 70 over ST Croix River?

It is owned by the State Highway Agency.