County profile · official public datasets

Carroll County, NH

193 public highway bridges tracked in the FHWA National Bridge Inventory: 54.9% rated Good, 40.9% Fair, 4.1% Poor.

193
Public bridges: 54.9%
Good condition: 4.1%
Poor condition

The verdict

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

Carroll County posts a top-10% lowest Poor-condition share among rated counties in the state across mid-size county bridge inventory.

Top 10%
lowest Poor share in state: 4.1%
Poor-condition share: 193
public highway bridges: 1966
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.

Carroll County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Carroll County ranks #1 of 10 New Hampshire counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 4.1%). Carroll County, New Hampshire contains 193 public highway bridges. Roughly 54.9% are rated “Good,” 40.9% “Fair,” and 4.1% “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

193

Public highway bridges in Carroll County

Good condition

54.9%

106 of 193 rated 7-9

Fair condition

40.9%

79 of 193 rated 5-6

Poor condition

4.1%

8 of 193 rated 4 or below

In-state Poor-share rank

#1 of 10

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

Condition distribution

Share of 193 NBI-tracked bridges by lowest applicable component rating.

Good

54.9% (106)

Fair

40.9% (79)

Poor

4.1% (8)

Carroll County's Poor-condition bridges carry 1,529 vehicle crossings a day

That is 0.3% of the county's reported daily bridge traffic on 4.1% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 191 crossings a day against 2,633 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 193 of 193 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

57.5% of Carroll County's bridges have passed the 50-year mark

111 of the 193 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 54.9% 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 68.1% of the county's Poor-condition bridge traffic

NH 16A over E BR SACO RIVER, built 1928, carries 1,041 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 8-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 1,529 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

pre-1900

4
1900s

5
1920s

13
1930s

25
1940s

14
1950s

21
1960s

20
1970s

28
1980s

13
1990s

14
2000s

13
2010s

12
2020s

11

What this shows Construction peaked in the 1970s, when 28 of the county's bridges still in the inventory were built, which is 14.5% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year (1966) matches the New Hampshire average (1968).

How Carroll County compares with New Hampshire's closest counties by inventory size

The 5 New Hampshire counties nearest Carroll County in number of bridges, with their condition splits. Its 4.1% Poor share is the 1st-lowest of these 6. Its average build year of 1966 against a peer-group mean of 1965 is in line with the group.

Showing the 5 closest of 9 New Hampshire counties eligible for comparison.

Bridge inventory size and condition shares for Carroll County and the 5 New Hampshire counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Carroll County (this page)	193	54.9%	40.9%	4.1%	1966
Cheshire County	192	41.7%	46.9%	11.5%	1960
Coos County	188	49.5%	44.1%	6.4%	1964
Sullivan County	158	45.6%	49.4%	5.1%	1963
Strafford County	136	63.2%	27.9%	8.8%	1971
Belknap County	112	58%	37.5%	4.5%	1969

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 Carroll 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 Carroll County, both outside New Hampshire so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside NH (193 bridges here).

Jo Daviess County, IL · 193 bridges
Cecil County, MD · 193 bridges
Blue Earth County, MN · 193 bridges
Jasper County, MS · 193 bridges

Similar average build year

Nearest mean year-built outside NH (1966 here).

Butler County, KS · avg 1966 · 591 bridges
Queens County, NY · avg 1966 · 514 bridges
Lehigh County, PA · avg 1966 · 381 bridges
Osage County, OK · avg 1966 · 366 bridges

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

All 193 Good 106 Fair 79 Poor 8

All bridges (193)

Sort:

Carroll County Bridge Snapshot

Condition distribution

Carroll County's Poor-condition bridges carry 1,529 vehicle crossings a day

57.5% of Carroll County's bridges have passed the 50-year mark

One structure carries 68.1% of the county's Poor-condition bridge traffic

How Carroll County compares with New Hampshire'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 (193)

DURGIN BRIDGE ROAD

EAST SIDE ROAD

NO DATA ENTERED

DRAKE ROAD

NH 16A

MAPLE STREET

OSSIPEE MT ROAD

UPPER ROAD

VALLEY CROSS ROAD

WHITEFACE INTERVAL

NH113

MIDDLE ROAD

NH109

FDR 34

MELLOON ROAD

WILSON ROAD

FOWLERS MILL ROAD

SODOM ROAD

FDR 38

NEW ROAD

BEAN MOUNTAIN ROAD

FDR 86

FDR 233

NH 16B

FDR 39

FDR 20

NO DATA ENTERED

RIVER ROAD

NO DATA ENTERED

BUTTER HILL ROAD

EAST MADISON ROAD

NH 16B

NH113A

WEST SIDE ROAD

NH 16

NH113A

NH 16A

NH 25

NH113

FDR 233

NH 16

TOWN HALL ROAD

NO DATA ENTERED

WASHINGTON STREET

NH 16

US302

SANDWICH NOTCH RD

DUNDEE ROAD

US302

FOWLERS MILL ROAD

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