County profile · official public datasets

Hunterdon County, NJ

373 public highway bridges tracked in the FHWA National Bridge Inventory: 20.1% rated Good, 72.4% Fair, 7.5% Poor.

373
Public bridges: 20.1%
Good condition: 7.5%
Poor condition

The verdict

According to the Federal Highway Administration's 2024 National Bridge Inventory.

Hunterdon County pairs a higher-than-median Poor-condition share among rated counties in the state with an older average build year than the state inventory.

15th
of 21 on Poor share: 7.5%
Poor-condition share: 373
public highway bridges: 1949
avg year built

Poor is an FHWA condition category from the lowest applicable component rating (4 or below), not a live crossing-safety or closure decision. Rankings cover counties with at least five public highway bridges.

Hunterdon County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Hunterdon County ranks #15 of 21 New Jersey counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 7.5%). Hunterdon County, New Jersey contains 373 public highway bridges. Roughly 20.1% are rated “Good,” 72.4% “Fair,” and 7.5% “Poor.” Poor means the lowest applicable deck, superstructure, substructure, or culvert rating is 4 or below on the 0–9 NBI scale. It is a condition category, not a live safety or closure decision.

Responsible agencies inspect covered bridges on risk-based intervals under current NBIS rules and submit inventory data to FHWA annually. The list below shows every NBI-tracked bridge in the county. Use the “Sort by” controls to change the ordering, and click any row for its reported inspection date, traffic count, and condition fields.

Source: FHWA National Bridge Inventory. See methodology for full definitions.

Total bridges

373

Public highway bridges in Hunterdon County

Good condition

20.1%

75 of 373 rated 7-9

Fair condition

72.4%

270 of 373 rated 5-6

Poor condition

7.5%

28 of 373 rated 4 or below

In-state Poor-share rank

#15 of 21

Among New Jersey counties with 5+ bridges, lower share ranks better

Condition distribution

Share of 373 NBI-tracked bridges by lowest applicable component rating.

Good

20.1% (75)

Fair

72.4% (270)

Poor

7.5% (28)

Hunterdon County's Poor-condition bridges carry 205,369 vehicle crossings a day

That is 4.2% of the county's reported daily bridge traffic on 7.5% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 7,335 crossings a day against 6,231 for a Good-condition one. A Poor rating is a condition category, not a closure or a live safety judgement; it means the lowest applicable component rating is 4 or below.

Computed over the 373 of 373 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

73.2% of Hunterdon County's bridges have passed the 50-year mark

273 of the 373 bridges with a recorded construction year were built in 1974 or earlier. Age alone is not a defect: a well-maintained older bridge can rate Good, and 20.1% of this county's inventory does. Even so, this older cohort is the population from which future Poor ratings are drawn, which is why the age profile below matters alongside the condition split above.

Cutoff derives from the 2024 release year minus a 50-year design life. Source: FHWA National Bridge Inventory, 2024 release.

One structure carries 62.4% of the county's Poor-condition bridge traffic

I-78 over BEAVER BROOK, built 1941, carries 128,249 vehicles a day, the most of any Poor-rated structure here. The county's Poor-condition exposure is concentrated rather than evenly spread, so the 28-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 205,369 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

pre-1900

30
1900s

43
1910s

13
1920s

39
1930s

40
1940s

13
1950s

26
1960s

57
1970s

15
1980s

18
1990s

23
2000s

40
2010s

12
2020s

4

What this shows Construction peaked in the 1960s, when 57 of the county's bridges still in the inventory were built, which is 15.3% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year is 1949, 17 years older than the New Jersey average of 1966.

How Hunterdon County compares with New Jersey's closest counties by inventory size

The 5 New Jersey counties nearest Hunterdon County in number of bridges, with their condition splits. Its 7.5% Poor share is the 3rd-lowest of these 6. Its average build year of 1949 against a peer-group mean of 1969 is 20 years older.

Showing the 5 closest of 20 New Jersey counties eligible for comparison.

Bridge inventory size and condition shares for Hunterdon County and the 5 New Jersey counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Mercer County	414	40.3%	50.5%	9.2%	1975
Union County	409	17.8%	78%	4.2%	1967
Somerset County	397	33%	57.4%	9.6%	1970
Hunterdon County (this page)	373	20.1%	72.4%	7.5%	1949
Burlington County	356	26.4%	63.5%	10.1%	1969
Passaic County	333	22.2%	74.5%	3.3%	1963

Each share is of that county's own total tracked bridges; peers are the counties with 5 or more bridges whose inventory size is closest to Hunterdon County's. Source: FHWA National Bridge Inventory, 2024 release.

Nationwide counties with similar inventory size or average build year

Two NBI-derived peer sets for Hunterdon County, both outside New Jersey so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside NJ (373 bridges here).

Solano County, CA · 373 bridges
Marion County, OR · 373 bridges
Benton County, IA · 374 bridges
Baltimore city County, MD · 374 bridges

Similar average build year

Nearest mean year-built outside NJ (1949 here).

Shackelford County, TX · avg 1949 · 78 bridges
Real County, TX · avg 1949 · 28 bridges
Armstrong County, TX · avg 1948 · 11 bridges
Castro County, TX · avg 1950 · 10 bridges

Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.

All 373 Good 75 Fair 270 Poor 28

All bridges (373)

Sort:

Hunterdon County Bridge Snapshot

Condition distribution

Hunterdon County's Poor-condition bridges carry 205,369 vehicle crossings a day

73.2% of Hunterdon County's bridges have passed the 50-year mark

One structure carries 62.4% of the county's Poor-condition bridge traffic

How Hunterdon County compares with New Jersey's closest counties by inventory size

Nationwide counties with similar inventory size or average build year

Similar inventory size

Similar average build year

All bridges (373)

NJ 29

COUNTY ROUTE 518

COUNTY ROUTE 518

I-78 EB

I-78 WB

MILFORD RD.

MOUNT JOY ROAD

COUNTY ROUTE 523

STONE SIGN POST RD

I-78 EB

ROCKAWAY ROAD

River Rd

CHERRY STREET

FARMERSVILLE ROAD

HOMESTEAD ROAD

WARSAW ROAD

PERRYVILLE ROAD

ACCESS ROAD

COUNTY ROUTE 623

I-78 E.B.

I-78 WB

NJ 31 NB

Taylors Mill Road

Chalfont Drive

PARK ENTRANCE ROAD

WATER STREET

COUNTY ROUTE 602

NJ 31 & US 202

I-78 WB

I-78 EB

I78 WB

IRON BRIDGE ROAD

USTP ENT/EX RAMP

WHISKEY LANE

COUNTY LINE ROAD

I-78 WB

I-78 EB

I-78 WB

NJ 29

COUNTY ROUTE 631

DECKERS CORNER RD.

I-78 WB

I-78 EB

NJ 179

CENTRAL STREET

OAK GROVE ROAD

NJ 12

US 22

JAVES ROAD

I-78 WB

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