US Bridges

US-91 (SR-91) over Logan River

Fair

Cache County, Utah · 600 South Main in Logan · Structure no. 0D 540

Built
1918
107 years old, rebuilt 1951
Condition
Fair
inspected July 2023
Type
Arch - Deck
Concrete
Length
98 ft
1 main span
Daily traffic
44,297
2022 count
Owner
State
State Highway Agency

About this bridge

US-91 (SR-91) over Logan River is a concrete arch - deck carrying US-91 (SR-91) over Logan River in Cache County, Utah. It was built in 1918 and reconstructed in 1951, so it is 107 years old, older than the Utah average of 40.1 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 44,297 vehicles a day, roughly 13% of them trucks, projected to reach 53,156 by 2042. The structure is 98 ft (29.9 m) long and 85 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesUS-91 (SR-91)
CrossesLogan River
Location600 South Main in Logan
RouteU.S. Route 91
CountyCache County
StateUtah
Coordinates41.72083, -111.83556
Functional classUrban Other Principal 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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating107.1 US tons
Inventory rating98.9 US tons

Structure

Structure typeArch - Deck
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadH 15
Structure length98 ft (29.9 m)
Longest span70 ft (21.3 m)
Deck width85 ft (25.8 m)
Roadway width72 ft (21.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic44,297 (2022)
Projected traffic53,156 by 2042
Trucks13%
Lanes on structure5
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusEligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was US-91 (SR-91) over Logan River built?

It was built in 1918, making it 107 years old in 2025. It was reconstructed in 1951.

What condition is US-91 (SR-91) over Logan 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 July 2023.

How much traffic does US-91 (SR-91) over Logan River carry?

About 44,297 vehicles per day (2022 count), of which roughly 13% are trucks.

How long is US-91 (SR-91) over Logan River?

The structure is 98 ft (29.9 m) long with a longest span of 70 ft (21.3 m) and a deck 85 ft wide.

Who owns US-91 (SR-91) over Logan River?

It is owned by the State Highway Agency.