US Bridges

M-66 over Manistee River

Fair

Kalkaska County, Michigan · 1.1MI N of Missaukee Col · Structure no. 000000000004696

Built
1979
46 years old
Condition
Fair
inspected June 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
159 ft
2 main spans
Daily traffic
1,150
2019 count
Owner
State
State Highway Agency

About this bridge

M-66 over Manistee River is a prestressed concrete stringer/multi-beam or girder carrying M-66 over Manistee River in Kalkaska County, Michigan. It was built in 1979, so it is 46 years old, younger than the Michigan average of 48.3 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 1,150 vehicles a day, roughly 10% of them trucks, projected to reach 1,323 by 2039. The structure is 159 ft (48.5 m) long and 52 ft wide. If it were closed, the detour would be 44.1 mi (71 km).

Location

Open in Google Maps
CarriesM-66
CrossesManistee River
Location1.1MI N of Missaukee Col
RouteState Highway 66
CountyKalkaska County
StateMichigan
Coordinates44.52372, -85.17189
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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
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 geometry9: Superior to present desirable criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating97.9 US tons
Inventory rating47.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans2
Design loadHS 25 or greater
Structure length159 ft (48.5 m)
Longest span78 ft (23.9 m)
Deck width52 ft (15.8 m)
Roadway width48 ft (14.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,150 (2019)
Projected traffic1,323 by 2039
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed44.1 mi (71 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 M-66 over Manistee River built?

It was built in 1979, making it 46 years old in 2025.

What condition is M-66 over Manistee 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 M-66 over Manistee River carry?

About 1,150 vehicles per day (2019 count), of which roughly 10% are trucks.

How long is M-66 over Manistee River?

The structure is 159 ft (48.5 m) long with a longest span of 78 ft (23.9 m) and a deck 52 ft wide.

Who owns M-66 over Manistee River?

It is owned by the State Highway Agency.