US Bridges

County Road over Souhegan River

Good

Hillsborough County, New Hampshire · 0.23MI Amherst Tl · Structure no. 016800450008900

Built
1987
38 years old
Condition
Good
inspected September 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
148 ft
2 main spans
Daily traffic
3,589
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

County Road over Souhegan River is a steel continuous stringer/multi-beam or girder carrying County Road over Souhegan River in Hillsborough 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 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 3,589 vehicles a day, roughly 4% of them trucks, projected to reach 5,311 by 2043. The structure is 148 ft (45.1 m) long and 32 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

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CarriesCounty Road
CrossesSouhegan River
Location0.23MI Amherst Tl
CountyHillsborough County
StateNew Hampshire
Coordinates42.83687, -71.56055
Functional classUrban Local

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 inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation7: Better than present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating49.3 US tons
Inventory rating36 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20 + Mod
Structure length148 ft (45.1 m)
Longest span72 ft (21.9 m)
Deck width32 ft (9.8 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,589 (2023)
Projected traffic5,311 by 2043
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal 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 County Road over Souhegan River built?

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

What condition is County Road over Souhegan 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 September 2023.

How much traffic does County Road over Souhegan River carry?

About 3,589 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is County Road over Souhegan River?

The structure is 148 ft (45.1 m) long with a longest span of 72 ft (21.9 m) and a deck 32 ft wide.

Who owns County Road over Souhegan River?

It is owned by the City or Municipal Highway Agency.