County profile · official public datasets

Mifflin County, PA

196 public highway bridges tracked in the FHWA National Bridge Inventory: 41.8% rated Good, 45.4% Fair, 12.8% Poor.

196
Public bridges: 41.8%
Good condition: 12.8%
Poor condition

The verdict

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

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

38th
of 67 on Poor share: 12.8%
Poor-condition share: 196
public highway bridges: 1974
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.

Mifflin County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Mifflin County ranks #38 of 67 Pennsylvania counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 12.8%). Mifflin County, Pennsylvania contains 196 public highway bridges. Roughly 41.8% are rated “Good,” 45.4% “Fair,” and 12.8% “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

196

Public highway bridges in Mifflin County

Good condition

41.8%

82 of 196 rated 7-9

Fair condition

45.4%

89 of 196 rated 5-6

Poor condition

12.8%

25 of 196 rated 4 or below

In-state Poor-share rank

#38 of 67

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

Condition distribution

Share of 196 NBI-tracked bridges by lowest applicable component rating.

Good

41.8% (82)

Fair

45.4% (89)

Poor

12.8% (25)

Mifflin County's Poor-condition bridges carry 17,272 vehicle crossings a day

That is 2.5% of the county's reported daily bridge traffic on 12.3% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 720 crossings a day against 3,704 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 195 of 196 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

48.5% of Mifflin County's bridges have passed the 50-year mark

95 of the 196 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 41.8% 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 22.2% of the county's Poor-condition bridge traffic

SR 2004 over SR 22-PA 22, built 1958, carries 3,831 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 25-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 17,272 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1900s

3
1910s

5
1920s

11
1930s

19
1940s

7
1950s

22
1960s

20
1970s

14
1980s

12
1990s

31
2000s

29
2010s

20
2020s

3

What this shows Construction peaked in the 1990s, when 31 of the county's bridges still in the inventory were built, which is 15.8% of those with a recorded year. That cohort is now 25 to 34 years old in the 2024 inventory. Its average build year (1974) matches the Pennsylvania average (1970).

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

The 5 Pennsylvania counties nearest Mifflin County in number of bridges, with their condition splits. Its 12.8% Poor share is the 3rd-lowest of these 6. Its average build year of 1974 against a peer-group mean of 1972 is in line with the group.

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

Bridge inventory size and condition shares for Mifflin County and the 5 Pennsylvania counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Clinton County	212	42.9%	54.7%	2.4%	1978
Potter County	207	44.9%	42%	13%	1979
Jefferson County	202	29.2%	63.9%	6.9%	1972
Mifflin County (this page)	196	41.8%	45.4%	12.8%	1974
Venango County	189	35.4%	49.7%	14.8%	1968
Perry County	183	32.2%	53.6%	14.2%	1965

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

Similar inventory size

Nearest county inventories outside PA (196 bridges here).

Page County, IA · 196 bridges
Wilkin County, MN · 196 bridges
Sampson County, NC · 196 bridges
Cherokee County, TX · 196 bridges

Similar average build year

Nearest mean year-built outside PA (1974 here).

Knox County, TN · avg 1974 · 588 bridges
Summit County, OH · avg 1974 · 563 bridges
Onondaga County, NY · avg 1974 · 472 bridges
Orange County, NY · avg 1974 · 472 bridges

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

All 196 Good 82 Fair 89 Poor 25

Poor-condition bridges (25)

Sort:

Mifflin County Bridge Snapshot

Condition distribution

Mifflin County's Poor-condition bridges carry 17,272 vehicle crossings a day

48.5% of Mifflin County's bridges have passed the 50-year mark

One structure carries 22.2% of the county's Poor-condition bridge traffic

How Mifflin 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

Poor-condition bridges (25)

T-391 ERTLEY ROAD

T-420

T-350

T-368 SPRING RUN

T-315

T-464

SR 2004

T-480

T-737 Alfarata Rd

REEDS GAP ROAD

T-783

T-472

T-439

SR 3006 SR 3006

SR 103-PA 103

T-465

T-439

T-321

T-803

SR 103-PA 103

T-458 TAYLOR MILL

WATER STREET

SR 2008

ON TSR 817

T-383 SNOOK ROAD

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