US Bridges

US302 Nh 10 over Ammonoosuc River

Good

Grafton County, New Hampshire · 2.9 MI from Carroll Tl · Structure no. 002401250017700

Built
1983
42 years old
Condition
Good
inspected May 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
401 ft
3 main spans
Daily traffic
3,265
2023 count
Owner
State
State Highway Agency

About this bridge

US302 Nh 10 over Ammonoosuc River is a steel continuous stringer/multi-beam or girder carrying US302 Nh 10 over Ammonoosuc River in Grafton County, New Hampshire. It was built in 1983, so it is 42 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 good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 3,265 vehicles a day, roughly 7% of them trucks, projected to reach 4,832 by 2043. The structure is 401 ft (122.2 m) long and 52 ft wide. If it were closed, the detour would be 13 mi (21 km).

CarriesUS302 Nh 10
CrossesAmmonoosuc River
Location2.9 MI from Carroll Tl
RouteU.S. Route 302
Coordinates44.27293, -71.63237
Functional classRural Principal Arterial - Other

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMay 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation7: Better than 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 rating65.1 US tons
Inventory rating39.1 US tons

Structure

MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length401 ft (122.2 m)
Longest span148 ft (45.1 m)
Deck width52 ft (15.7 m)
Roadway width43 ft (13.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,265 (2023)
Projected traffic4,832 by 2043
Trucks7%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed13 mi (21 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 Nh 10 over Ammonoosuc River built?

It was built in 1983, making it 42 years old in 2025.

What condition is US302 Nh 10 over Ammonoosuc River in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in May 2024.

How much traffic does US302 Nh 10 over Ammonoosuc River carry?

About 3,265 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is US302 Nh 10 over Ammonoosuc River?

The structure is 401 ft (122.2 m) long with a longest span of 148 ft (45.1 m) and a deck 52 ft wide.

Who owns US302 Nh 10 over Ammonoosuc River?

It is owned by the State Highway Agency.