US Bridges

US 4 over Stony Brook

Fair

Grafton County, New Hampshire · 2.8 Mi. from Enfield T.L. · Structure no. 014401670010600

Built
1966
59 years old
Condition
Fair
inspected June 2023
Type
Culvert
Concrete
Length
34 ft
2 main spans
Daily traffic
12,439
2023 count
Owner
State
State Highway Agency

About this bridge

US 4 over Stony Brook is a concrete culvert carrying US 4 over Stony Brook in Grafton County, New Hampshire. It was built in 1966, so it is 59 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 12,439 vehicles a day, roughly 7% of them trucks, projected to reach 18,409 by 2043. The structure is 34 ft (10.4 m) long. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesUS 4
CrossesStony Brook
Location2.8 Mi. from Enfield T.L.
RouteU.S. Route 4
CountyGrafton County
StateNew Hampshire
Coordinates43.63417, -72.20808
Functional classUrban Minor Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
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
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating69.8 US tons
Inventory rating41.8 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans2
Design loadHS 20
Structure length34 ft (10.4 m)
Longest span15 ft (4.6 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic12,439 (2023)
Projected traffic18,409 by 2043
Trucks7%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemNo
Strategic Highway NetworkInterstate STRAHNET route

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 US 4 over Stony Brook built?

It was built in 1966, making it 59 years old in 2025.

What condition is US 4 over Stony Brook 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 US 4 over Stony Brook carry?

About 12,439 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is US 4 over Stony Brook?

The structure is 34 ft (10.4 m) long with a longest span of 15 ft (4.6 m).

Who owns US 4 over Stony Brook?

It is owned by the State Highway Agency.