US Bridges

Mill Brook Road over Mill Brook

Fair

Grafton County, New Hampshire · 3.3 MI S. Jct. 302 · Structure no. 014201040013100

Built
1928
97 years old
Condition
Fair
inspected June 2023
Type
Arch - Deck
Concrete
Length
25 ft
1 main span
Daily traffic
177
2023 count
Owner
State
State Highway Agency

About this bridge

Mill Brook Road over Mill Brook is a concrete arch - deck carrying Mill Brook Road over Mill Brook in Grafton County, New Hampshire. It was built in 1928, so it is 97 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 177 vehicles a day, projected to reach 261 by 2043. The structure is 25 ft (7.6 m) long and 23 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesMill Brook Road
CrossesMill Brook
Location3.3 MI S. Jct. 302
RouteState Highway 0
CountyGrafton County
StateNew Hampshire
Coordinates44.16819, -71.89165
Functional classRural Minor 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.
Substructure7 GoodSome minor problems.
Channel and channel protection6 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
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating50.4 US tons
Inventory rating30.2 US tons

Structure

Structure typeArch - Deck
MaterialConcrete
DeckNot applicable
Main spans1
Design loadH 15
Structure length25 ft (7.6 m)
Longest span25 ft (7.6 m)
Deck width23 ft (7.1 m)
Roadway width21 ft (6.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic177 (2023)
Projected traffic261 by 2043
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

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 Mill Brook Road over Mill Brook built?

It was built in 1928, making it 97 years old in 2025.

What condition is Mill Brook Road over Mill 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 Mill Brook Road over Mill Brook carry?

About 177 vehicles per day (2023 count).

How long is Mill Brook Road over Mill Brook?

The structure is 25 ft (7.6 m) long with a longest span of 25 ft (7.6 m) and a deck 23 ft wide.

Who owns Mill Brook Road over Mill Brook?

It is owned by the State Highway Agency.