US Bridges

US302 over Ammonoosuc River

Fair

Coos County, New Hampshire · 4.46 MI E JCT US 3 · Structure no. 003901730014100

Built
1987
38 years old
Condition
Fair
inspected June 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
111 ft
1 main span
Daily traffic
3,842
2023 count
Owner
State
State Highway Agency

About this bridge

US302 over Ammonoosuc River is a steel stringer/multi-beam or girder carrying US302 over Ammonoosuc River in Coos County, New Hampshire. It was built in 1987, so it is 38 years old, younger than the New Hampshire average of 56.9 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 3,842 vehicles a day, roughly 7% of them trucks, projected to reach 5,686 by 2043. The structure is 111 ft (33.8 m) long and 55 ft wide. If it were closed, the detour would be 47.8 mi (77 km).

Location

Open in Google Maps
CarriesUS302
CrossesAmmonoosuc River
Location4.46 MI E JCT US 3
RouteU.S. Route 302
CountyCoos County
StateNew Hampshire
Coordinates44.2626, -71.45746
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
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
Deck geometry9: Superior to present desirable criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating76.1 US tons
Inventory rating45.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20 + Mod
Structure length111 ft (33.8 m)
Longest span106 ft (32.3 m)
Deck width55 ft (16.9 m)
Roadway width48 ft (14.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,842 (2023)
Projected traffic5,686 by 2043
Trucks7%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed47.8 mi (77 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$314,000 (2025 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was US302 over Ammonoosuc River built?

It was built in 1987, making it 38 years old in 2025.

What condition is US302 over Ammonoosuc 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 US302 over Ammonoosuc River carry?

About 3,842 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is US302 over Ammonoosuc River?

The structure is 111 ft (33.8 m) long with a longest span of 106 ft (32.3 m) and a deck 55 ft wide.

Who owns US302 over Ammonoosuc River?

It is owned by the State Highway Agency.