US Bridges

Mn 61 over Split Rock River

Fair

Lake County, Minnesota · 4.5 MI NE of JCT Csah 1 · Structure no. 9405

Built
1958
67 years old
Condition
Fair
inspected June 2023
Type
Culvert
Concrete
Length
41 ft
3 main spans
Daily traffic
3,875
2022 count
Owner
State
State Highway Agency

About this bridge

Mn 61 over Split Rock River is a concrete culvert carrying Mn 61 over Split Rock River in Lake County, Minnesota. It was built in 1958, so it is 67 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 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 3,875 vehicles a day, roughly 11% of them trucks, projected to reach 4,400 by 2042. The structure is 41 ft (12.5 m) long. If it were closed, the detour would be 6.2 mi (10 km).

Location

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CarriesMn 61
CrossesSplit Rock River
Location4.5 MI NE of JCT Csah 1
RouteState Highway 61
CountyLake County
StateMinnesota
Coordinates47.1829, -91.40846
Functional classRural Principal Arterial - Other

Condition and inspection

Fair

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

ComponentRatingMeaning
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating43.2 US tons
Inventory rating32.4 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans3
Design loadHS 20
Structure length41 ft (12.5 m)
Longest span14 ft (4.3 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,875 (2022)
Projected traffic4,400 by 2042
Trucks11%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.2 mi (10 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkNon-Interstate STRAHNET route

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$94 million
NavigationNo navigation control on waterway

Frequently asked questions

When was Mn 61 over Split Rock River built?

It was built in 1958, making it 67 years old in 2025.

What condition is Mn 61 over Split Rock 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 61 over Split Rock River carry?

About 3,875 vehicles per day (2022 count), of which roughly 11% are trucks.

How long is Mn 61 over Split Rock River?

The structure is 41 ft (12.5 m) long with a longest span of 14 ft (4.3 m).

Who owns Mn 61 over Split Rock River?

It is owned by the State Highway Agency.