US Bridges

NH120 over Mink Brook

Fair

Grafton County, New Hampshire · .3 Mi. from Lebanon Tl · Structure no. 011400630004700

Built
1969
56 years old
Condition
Fair
inspected April 2024
Type
Culvert
Concrete
Length
21 ft
1 main span
Daily traffic
10,035
2023 count
Owner
State
State Highway Agency

About this bridge

NH120 over Mink Brook is a concrete culvert carrying NH120 over Mink Brook in Grafton County, New Hampshire. It was built in 1969, so it is 56 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 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 10,035 vehicles a day, roughly 5% of them trucks, projected to reach 14,851 by 2043. The structure is 21 ft (6.4 m) long. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesNH120
CrossesMink Brook
Location.3 Mi. from Lebanon Tl
RouteState Highway 120
CountyGrafton County
StateNew Hampshire
Coordinates43.68998, -72.26916
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 protection7 GoodSome minor problems.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionApril 2024
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 rating99 US tons
Inventory rating99 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans1
Design loadHS 20
Structure length21 ft (6.4 m)
Longest span21 ft (6.4 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic10,035 (2023)
Projected traffic14,851 by 2043
Trucks5%
Lanes on structure3
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed5 mi (8 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 NH120 over Mink Brook built?

It was built in 1969, making it 56 years old in 2025.

What condition is NH120 over Mink 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 April 2024.

How much traffic does NH120 over Mink Brook carry?

About 10,035 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is NH120 over Mink Brook?

The structure is 21 ft (6.4 m) long with a longest span of 21 ft (6.4 m).

Who owns NH120 over Mink Brook?

It is owned by the State Highway Agency.