US Bridges

Wilton Road over Souhegan River

Fair

Hillsborough County, New Hampshire · 200 W of Elm ST (NH101) · Structure no. 017200520013500

Built
1917
108 years old, rebuilt 1952
Condition
Fair
inspected June 2024
Type
Arch - Deck
Masonry
Length
152 ft
2 main spans
Daily traffic
6,406
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

Wilton Road over Souhegan River is a masonry arch - deck carrying Wilton Road over Souhegan River in Hillsborough County, New Hampshire. It was built in 1917 and reconstructed in 1952, so it is 108 years old, older 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 6,406 vehicles a day, roughly 4% of them trucks, projected to reach 9,480 by 2043. The structure is 152 ft (46.3 m) long and 28 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

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CarriesWilton Road
CrossesSouhegan River
Location200 W of Elm ST (NH101)
CountyHillsborough County
StateNew Hampshire
Coordinates42.84136, -71.72055
Functional classUrban Collector

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 protection7 GoodSome minor problems.
Last inspectionJune 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating36.3 US tons
Inventory rating24.1 US tons

Structure

Structure typeArch - Deck
MaterialMasonry
DeckOther
Main spans2
Design loadH 15
Structure length152 ft (46.3 m)
Longest span60 ft (18.3 m)
Deck width28 ft (8.5 m)
Roadway width23 ft (7.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,406 (2023)
Projected traffic9,480 by 2043
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal Highway Agency
Historic statusEligible 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 Wilton Road over Souhegan River built?

It was built in 1917, making it 108 years old in 2025. It was reconstructed in 1952.

What condition is Wilton Road over Souhegan 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 2024.

How much traffic does Wilton Road over Souhegan River carry?

About 6,406 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is Wilton Road over Souhegan River?

The structure is 152 ft (46.3 m) long with a longest span of 60 ft (18.3 m) and a deck 28 ft wide.

Who owns Wilton Road over Souhegan River?

It is owned by the City or Municipal Highway Agency.