US Bridges

US302 Nh 10 over Mill Brook

Fair

Grafton County, New Hampshire · 0.1 MI East of Bath Tl · Structure no. 014200670017300

Built
1930
95 years old
Condition
Fair
inspected August 2023
Type
Culvert
Concrete
Length
24 ft
1 main span
Daily traffic
3,081
2023 count
Owner
State
State Highway Agency

About this bridge

US302 Nh 10 over Mill Brook is a concrete culvert carrying US302 Nh 10 over Mill Brook in Grafton County, New Hampshire. It was built in 1930, so it is 95 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 3,081 vehicles a day, roughly 7% of them trucks, projected to reach 4,559 by 2043. The structure is 24 ft (7.3 m) long. If it were closed, the detour would be 6.2 mi (10 km).

Location

Open in Google Maps
CarriesUS302 Nh 10
CrossesMill Brook
Location0.1 MI East of Bath Tl
RouteU.S. Route 302
CountyGrafton County
StateNew Hampshire
Coordinates44.19934, -71.93061
Functional classRural 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 inspectionAugust 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 rating60 US tons
Inventory rating36 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans1
Design loadH 15
Structure length24 ft (7.3 m)
Longest span24 ft (7.3 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,081 (2023)
Projected traffic4,559 by 2043
Trucks7%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.2 mi (10 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 US302 Nh 10 over Mill Brook built?

It was built in 1930, making it 95 years old in 2025.

What condition is US302 Nh 10 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 August 2023.

How much traffic does US302 Nh 10 over Mill Brook carry?

About 3,081 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is US302 Nh 10 over Mill Brook?

The structure is 24 ft (7.3 m) long with a longest span of 24 ft (7.3 m).

Who owns US302 Nh 10 over Mill Brook?

It is owned by the State Highway Agency.