County profile · official public datasets

Strafford County, NH

136 public highway bridges tracked in the FHWA National Bridge Inventory: 63.2% rated Good, 27.9% Fair, 8.8% Poor.

136
Public bridges: 63.2%
Good condition: 8.8%
Poor condition

The verdict

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

Strafford County posts a higher-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.

8th
of 10 on Poor share: 8.8%
Poor-condition share: 136
public highway bridges: 1971
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.

Strafford County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Strafford County ranks #8 of 10 New Hampshire counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 8.8%). Strafford County, New Hampshire contains 136 public highway bridges. Roughly 63.2% are rated “Good,” 27.9% “Fair,” and 8.8% “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

136

Public highway bridges in Strafford County

Good condition

63.2%

86 of 136 rated 7-9

Fair condition

27.9%

38 of 136 rated 5-6

Poor condition

8.8%

12 of 136 rated 4 or below

In-state Poor-share rank

#8 of 10

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

Condition distribution

Share of 136 NBI-tracked bridges by lowest applicable component rating.

Good

63.2% (86)

Fair

27.9% (38)

Poor

8.8% (12)

Strafford County's Poor-condition bridges carry 119,363 vehicle crossings a day

That is 9% of the county's reported daily bridge traffic on 8.8% of its bridges: Poor-condition structures carry more traffic than their share of the inventory. Each Poor bridge averages 9,947 crossings a day against 9,685 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 136 of 136 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

50.7% of Strafford County's bridges have passed the 50-year mark

69 of the 136 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 63.2% 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 19.3% of the county's Poor-condition bridge traffic

NH 16 SP TPK SB over COCHECO RIVER, built 1957, carries 23,076 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 12-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 119,363 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

pre-1900

2
1900s

2
1910s

2
1920s

8
1930s

7
1940s

4
1950s

30
1960s

12
1970s

14
1980s

20
1990s

6
2000s

6
2010s

19
2020s

4

What this shows Construction peaked in the 1950s, when 30 of the county's bridges still in the inventory were built, which is 22.1% of those with a recorded year. That cohort is now 65 to 74 years old in the 2024 inventory. Its average build year (1971) matches the New Hampshire average (1968).

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

The 5 New Hampshire counties nearest Strafford County in number of bridges, with their condition splits. Its 8.8% Poor share is the 5th-lowest of these 6. Its average build year of 1971 against a peer-group mean of 1964 is 7 years newer.

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

Bridge inventory size and condition shares for Strafford County and the 5 New Hampshire counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Carroll County	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 (this page)	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 Strafford 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 Strafford County, both outside New Hampshire so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside NH (136 bridges here).

Bullock County, AL · 136 bridges
Jackson County, AR · 136 bridges
Perry County, IL · 136 bridges
Lincoln County, KY · 136 bridges

Similar average build year

Nearest mean year-built outside NH (1971 here).

Wayne County, MI · avg 1971 · 1,026 bridges
Baltimore County, MD · avg 1971 · 783 bridges
Washington County, PA · avg 1971 · 655 bridges
Linn County, OR · avg 1971 · 566 bridges

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

All 136 Good 86 Fair 38 Poor 12

Good-condition bridges (86)

Sort:

Strafford County Bridge Snapshot

Condition distribution

Strafford County's Poor-condition bridges carry 119,363 vehicle crossings a day

50.7% of Strafford County's bridges have passed the 50-year mark

One structure carries 19.3% of the county's Poor-condition bridge traffic

How Strafford 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

Good-condition bridges (86)

NH108

US202 NH 11

US202 NH 11 SP TPK

TOLEND ROAD

INNOVATION DRIVE

SIXTH STREET

NH 11

NH153

NH 16 SP TPK

WASHINGTON STREET

NH 16 SP TPK SB

NH 16 SP TPK NB

US202 NH 16 SP TPK

NH 16 SP TPK

HIGH STREET

LITTLE FALLS BR RD

SP TPK NB OFF RAMP

NH 16 SP TPK RAMP

NH 75

BRIDGE STREET

NH 16 SP TPK

ROLLINS ROAD

SPRING STREET

US202 NH 11 SP TPK

MILTON ROAD

NH 75 CENTRAL ST

SP TPK SB ON RAMP

FLAT ROCK BR RD

NH 16 SP TPK RAMP

NUTE ROAD

US 4 WB

WISWALL ROAD

NH155

MALLEGO ROAD

NH 16 SP TPK

NH 16 SP TPK

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