County profile · official public datasets

Blair County, PA

338 public highway bridges tracked in the FHWA National Bridge Inventory: 39.1% rated Good, 50.9% Fair, 10.1% Poor.

338
Public bridges: 39.1%
Good condition: 10.1%
Poor condition

The verdict

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

Blair County pairs a better-than-median Poor-condition share among rated counties in the state with a newer average build year than the state inventory.

Top 40%
lowest Poor share in state: 10.1%
Poor-condition share: 338
public highway bridges: 1976
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.

Blair County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Blair County ranks #27 of 67 Pennsylvania counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 10.1%). Blair County, Pennsylvania contains 338 public highway bridges. Roughly 39.1% are rated “Good,” 50.9% “Fair,” and 10.1% “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

338

Public highway bridges in Blair County

Good condition

39.1%

132 of 338 rated 7-9

Fair condition

50.9%

172 of 338 rated 5-6

Poor condition

10.1%

34 of 338 rated 4 or below

In-state Poor-share rank

#27 of 67

Among Pennsylvania counties with 5+ bridges, lower share ranks better

Condition distribution

Share of 338 NBI-tracked bridges by lowest applicable component rating.

Good

39.1% (132)

Fair

50.9% (172)

Poor

10.1% (34)

Blair County's Poor-condition bridges carry 27,955 vehicle crossings a day

That is 1.9% of the county's reported daily bridge traffic on 10.1% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 822 crossings a day against 4,843 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 338 of 338 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

40.5% of Blair County's bridges have passed the 50-year mark

137 of the 338 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 39.1% 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 20.4% of the county's Poor-condition bridge traffic

25TH AVENUE over SPRING RUN, built 1961, carries 5,701 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 34-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 27,955 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

pre-1900

2
1900s

4
1910s

11
1920s

8
1930s

28
1940s

10
1950s

31
1960s

25
1970s

30
1980s

73
1990s

36
2000s

32
2010s

40
2020s

8

What this shows Construction peaked in the 1980s, when 73 of the county's bridges still in the inventory were built, which is 21.6% of those with a recorded year. That cohort is now 35 to 44 years old in the 2024 inventory. Its average build year is 1976, 6 years newer than the Pennsylvania average of 1970.

How Blair County compares with Pennsylvania's closest counties by inventory size

The 5 Pennsylvania counties nearest Blair County in number of bridges, with their condition splits. Its 10.1% Poor share is the 4th-lowest of these 6. Its average build year of 1976 against a peer-group mean of 1973 is in line with the group.

Showing the 5 closest of 66 Pennsylvania counties eligible for comparison.

Bridge inventory size and condition shares for Blair County and the 5 Pennsylvania counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Centre County	367	48%	46%	6%	1982
Lackawanna County	363	36.6%	45.7%	17.6%	1972
Northampton County	356	31.2%	59.6%	9.3%	1970
Cumberland County	348	39.1%	56%	4.9%	1975
Blair County (this page)	338	39.1%	50.9%	10.1%	1976
Monroe County	315	26.3%	52.7%	21%	1966

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 Blair 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 Blair County, both outside Pennsylvania so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside PA (338 bridges here).

Carter County, OK · 339 bridges
Placer County, CA · 337 bridges
Tama County, IA · 337 bridges
Cowley County, KS · 337 bridges

Similar average build year

Nearest mean year-built outside PA (1976 here).

Marion County, IN · avg 1976 · 958 bridges
Mohave County, AZ · avg 1976 · 641 bridges
Comanche County, OK · avg 1976 · 593 bridges
Prince George's County, MD · avg 1976 · 576 bridges

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

All 338 Good 132 Fair 172 Poor 34

All bridges (338)

Sort:

T424 SCOTCH VALLEY

Good

Over: BRUSH RUN

1 MI.NE.OF HOLLIDAYSBURG, Blair, PA

Built 1987 Load: 70.8 t ADT: 3,120

T454 Lwr Clover Cr

Good

Over: CLOVER CREEK

1 MI.E.OF WILLIAMSBURG, Blair, PA

Built 1939 Load: 70.8 t ADT: 199

SR 4013

Good

Over: SPRING RUN

ALTOONA JUNIATA, Blair, PA

Built 2003 Load: 89.7 t ADT: 9,470

SR 4008

Good

Over: KITTANNING RUN

3 MI.W.OF ALTOONA, Blair, PA

Blair County Bridge Snapshot

Condition distribution

Blair County's Poor-condition bridges carry 27,955 vehicle crossings a day

40.5% of Blair County's bridges have passed the 50-year mark

One structure carries 20.4% of the county's Poor-condition bridge traffic

How Blair County compares with Pennsylvania'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 (338)

T424 SCOTCH VALLEY

T454 Lwr Clover Cr

SR 4013

SR 4008

T427 White BridgeR

UPPER RES.PARK RD.

T435 Blue Hole Rd

T-364 CHAPPELL RD

13TH STREET

SR 3008(LOBSTOR)

T-463 Etna Furnace

WEST CHESTNUT AVE.

T527 DECKER HOLLOW

T-525 HELSEL ROAD

T376 Shaw Road

T512 Irish Flats L

13TH STREET

25TH AVENUE

NORTH AVENUE

SR 1012

T456 Old Mill Run

16TH STREET

T551 PLUMMER HOLLO

T734 KELSEY ROAD

T-349 Mountain Rd

T433 Church Road

CR-101 Bedford St

CO RD 101 Bedfrd S

BROAD AVENUE

12TH STREET

T352 Butler Hlw Rd

T378 LWR PINEY CRK

T-328 CREPS ROAD

T-397 Biddle Road

T381 Negley Spring

T617 DOGWOOD DRIVE

16TH STREET

T484 SICKL CR BK R

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