US Bridges

Mn 99 over Minnesota River

Fair

Le Sueur County, Minnesota · In ST Peter · Structure no. 4930

Built
1931
94 years old
Condition
Fair
inspected May 2024
Type
Truss - Thru
Steel Continuous
Length
402 ft
2 main spans
Daily traffic
5,548
2022 count
Owner
State
State Highway Agency

About this bridge

Mn 99 over Minnesota River is a steel continuous truss - thru carrying Mn 99 over Minnesota River in Le Sueur County, Minnesota. It was built in 1931, so it is 94 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 5,548 vehicles a day, roughly 9% of them trucks, projected to reach 6,700 by 2042. The structure is 402 ft (122.6 m) long and 31 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

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CarriesMn 99
CrossesMinnesota River
LocationIn ST Peter
RouteState Highway 99
CountyLe Sueur County
StateMinnesota
Coordinates44.32479, -93.95314
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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMay 2024
Inspection intervalevery 12 months
Operating statusOpen, no restriction
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating38.6 US tons
Inventory rating29.7 US tons

Structure

Structure typeTruss - Thru
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans2 (+2 approach)
Design loadH 15
Structure length402 ft (122.6 m)
Longest span196 ft (59.8 m)
Deck width31 ft (9.5 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deck15 ft (4.7 m)

Traffic and service

Average daily traffic5,548 (2022)
Projected traffic6,700 by 2042
Trucks9%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed5 mi (8 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusListed on the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost$1,000 million
NavigationNo navigation control on waterway

Frequently asked questions

When was Mn 99 over Minnesota River built?

It was built in 1931, making it 94 years old in 2025.

What condition is Mn 99 over Minnesota 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 May 2024.

How much traffic does Mn 99 over Minnesota River carry?

About 5,548 vehicles per day (2022 count), of which roughly 9% are trucks.

How long is Mn 99 over Minnesota River?

The structure is 402 ft (122.6 m) long with a longest span of 196 ft (59.8 m) and a deck 31 ft wide.

Who owns Mn 99 over Minnesota River?

It is owned by the State Highway Agency.