US Bridges

US302 over Ammonoosuc River

Fair

Coos County, New Hampshire · 3.5 Mi. East Int US3 · Structure no. 003901620012700

Built
1974
51 years old
Condition
Fair
inspected June 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
206 ft
3 main spans
Daily traffic
4,075
2023 count
Owner
State
State Highway Agency

About this bridge

US302 over Ammonoosuc River is a steel continuous stringer/multi-beam or girder carrying US302 over Ammonoosuc River in Coos County, New Hampshire. It was built in 1974, so it is 51 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 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 4,075 vehicles a day, roughly 7% of them trucks, projected to reach 6,031 by 2043. The structure is 206 ft (62.8 m) long and 47 ft wide. If it were closed, the detour would be 18 mi (29 km).

Location

Open in Google Maps
CarriesUS302
CrossesAmmonoosuc River
Location3.5 Mi. East Int US3
RouteU.S. Route 302
CountyCoos County
StateNew Hampshire
Coordinates44.26922, -71.47574
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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection4 PoorAdvanced section loss, deterioration, spalling or scour.
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 geometry6: Equal to present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating57.2 US tons
Inventory rating34.2 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length206 ft (62.8 m)
Longest span70 ft (21.3 m)
Deck width47 ft (14.2 m)
Roadway width43 ft (13 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,075 (2023)
Projected traffic6,031 by 2043
Trucks7%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed18 mi (29 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
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 1974, making it 51 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 4,075 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is US302 over Ammonoosuc River?

The structure is 206 ft (62.8 m) long with a longest span of 70 ft (21.3 m) and a deck 47 ft wide.

Who owns US302 over Ammonoosuc River?

It is owned by the State Highway Agency.