US Bridges

Rainbow Hill Road over Neshanic River

FairPosted for load

Hunterdon County, New Jersey · 0.4 MI North of CR 602 · Structure no. 100E228

Built
1900
125 years old, rebuilt 1995
Condition
Fair
inspected March 2023
Type
Truss - Thru
Steel
Length
153 ft
2 main spans
Daily traffic
191
2023 count
Owner
County
County Highway Agency

About this bridge

Rainbow Hill Road over Neshanic River is a steel truss - thru carrying Rainbow Hill Road over Neshanic River in Hunterdon County, New Jersey. It was built in 1900 and reconstructed in 1995, so it is 125 years old, older than the New Jersey average of 58.5 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. Its operating status is: posted for load restriction.

It carries about 191 vehicles a day, projected to reach 230 by 2043. The structure is 153 ft (46.6 m) long and 14 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

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CarriesRainbow Hill Road
CrossesNeshanic River
Location0.4 MI North of CR 602
CountyHunterdon County
StateNew Jersey
Coordinates40.47011, -74.77867
Functional classRural Local

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionMarch 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour within limits of footing or piles
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 adequacy7: Better than present minimum criteria
Approach roadway alignment3: Basically intolerable, requiring high priority of corrective action
Operating rating31 US tons
Inventory rating19 US tons

Structure

Structure typeTruss - Thru
MaterialSteel
DeckWood or timber
Main spans2
Design loadHS 20
Structure length153 ft (46.6 m)
Longest span75 ft (22.9 m)
Deck width14 ft (4.3 m)
Roadway width13 ft (4.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic191 (2023)
Projected traffic230 by 2043
Trucks0%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$3 million (2023 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Rainbow Hill Road over Neshanic River built?

It was built in 1900, making it 125 years old in 2025. It was reconstructed in 1995.

What condition is Rainbow Hill Road over Neshanic 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 March 2023.

How much traffic does Rainbow Hill Road over Neshanic River carry?

About 191 vehicles per day (2023 count).

How long is Rainbow Hill Road over Neshanic River?

The structure is 153 ft (46.6 m) long with a longest span of 75 ft (22.9 m) and a deck 14 ft wide.

Who owns Rainbow Hill Road over Neshanic River?

It is owned by the County Highway Agency.