County profile · official public datasets

Mercer County, PA

438 public highway bridges tracked in the FHWA National Bridge Inventory: 39.3% rated Good, 45.2% Fair, 15.5% Poor.

438
Public bridges: 39.3%
Good condition: 15.5%
Poor condition

The verdict

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

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

51st
of 67 on Poor share: 15.5%
Poor-condition share: 438
public highway bridges: 1972
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.

Mercer County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Mercer County ranks #51 of 67 Pennsylvania counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 15.5%). Mercer County, Pennsylvania contains 438 public highway bridges. Roughly 39.3% are rated “Good,” 45.2% “Fair,” and 15.5% “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

438

Public highway bridges in Mercer County

Good condition

39.3%

172 of 438 rated 7-9

Fair condition

45.2%

198 of 438 rated 5-6

Poor condition

15.5%

68 of 438 rated 4 or below

In-state Poor-share rank

#51 of 67

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

Condition distribution

Share of 438 NBI-tracked bridges by lowest applicable component rating.

Good

39.3% (172)

Fair

45.2% (198)

Poor

15.5% (68)

Mercer County's Poor-condition bridges carry 67,582 vehicle crossings a day

That is 5.7% of the county's reported daily bridge traffic on 15.3% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 1,009 crossings a day against 2,263 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 437 of 438 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

59.6% of Mercer County's bridges have passed the 50-year mark

261 of the 438 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 39.3% 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 14.5% of the county's Poor-condition bridge traffic

SR 58 MAIN STREET over OVER WOLF CREEK, built 1967, carries 9,802 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 68-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 67,582 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

pre-1900

5
1900s

7
1910s

7
1920s

14
1930s

19
1940s

7
1950s

40
1960s

147
1970s

34
1980s

46
1990s

42
2000s

27
2010s

40
2020s

3

What this shows Construction peaked in the 1960s, when 147 of the county's bridges still in the inventory were built, which is 33.6% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year (1972) matches the Pennsylvania average (1970).

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

The 5 Pennsylvania counties nearest Mercer County in number of bridges, with their condition splits. Its 15.5% Poor share is the 5th-lowest of these 6. Its average build year of 1972 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 Mercer County and the 5 Pennsylvania counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Somerset County	454	33%	52.6%	14.3%	1969
Dauphin County	449	22%	69.5%	8.5%	1972
Erie County	442	37.8%	52.7%	9.5%	1976
Mercer County (this page)	438	39.3%	45.2%	15.5%	1972
Tioga County	429	49.4%	47.3%	3.3%	1977
Fayette County	422	39.6%	42.7%	17.8%	1971

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

Similar inventory size

Nearest county inventories outside PA (438 bridges here).

Licking County, OH · 439 bridges
Butte County, CA · 437 bridges
Clay County, MO · 436 bridges
Pinellas County, FL · 435 bridges

Similar average build year

Nearest mean year-built outside PA (1972 here).

Santa Clara County, CA · avg 1972 · 964 bridges
Madison County, AL · avg 1972 · 710 bridges
Kern County, CA · avg 1972 · 668 bridges
Middlesex County, NJ · avg 1972 · 563 bridges

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

All 438 Good 172 Fair 198 Poor 68

All bridges (438)

Sort:

BRIDGE 2611 T-730

Good

Over: OVER MILL CREEK

ANDRUSKY RD FINDLEY TWP., Mercer, PA

Built 1969 Load: 59.9 t ADT: 412

BRIDGE 112 T-374

Good

Over: OVER SUGAR RUN

SUGAR RUN RD. GREENE TWP., Mercer, PA

Built 1990 Load: 59.9 t ADT: 81

BAKER HILL ROAD

Good

Over: SUGAR RUN

DELAWARE TWP., Mercer, PA

Built 2010 Load: 59.9 t ADT: 226

BRIDGE 1218 T-703

Good

Over: OVER SMALL CREEK

VOGAN RD. MILL CREEK TWP., Mercer, PA

Built 1987 Load: 60.8 t ADT: 41

SR 718 STATE ST

Good

Over: SHENANGO RIVER

CITY SHARON, Mercer, PA

Built 2007 Load: 61.7 t ADT: 4,628

SUNOL ROAD

Good

Over: OVER NORTH DEER CREEK TR

SUNOL RD FRENCH CK. TWP., Mercer, PA

Built 1994 Load: 62.6 t ADT: 151

BRIDGE 1317 T-422

Good

Over: OVER BRUSH RUN

SHENANGO PK.RD.PYM.TWP., Mercer, PA

Built 1967 Load: 64.4 t ADT: 858

SR 3022 RUTLEDGE R

Good

Over: OVER LACKAWANNOCK CREEK

JEFFERSON TOWNSHIP, Mercer, PA

Built 1999 Load: 67.1 t ADT: 258

SR 4021 BEATTY SCH

Good

Over: SHENANGO RIVER TRIB

SUGAR GROVE TOWNSHIP, Mercer, PA

Built 2003 Load: 68.0 t ADT: 132

BRIDGE 1315 T-589

Good

Over: OVER SHENANGO RIVER BR.

E.LAKE RD. PYMATUNING TWP, Mercer, PA

Built 1965 Load: 68.9 t ADT: 765

SR 1004 Stoneboro

Good

Over: COOLSPRING CREEK

FAIRVIEW TWP, Mercer, PA

Built 2010 Load: 69.9 t ADT: 391

SR 4001 N SUMMIT

Good

Over: SUGAR RUN TRIB

GREENE TWP, Mercer, PA

Built 2013 Load: 74.5 t ADT: 190

BRIDGE 2106

Good

Over: OVER UNNAMED TR.FOX RUN

FOX MINE RD.JACKSON TWP., Mercer, PA

Built 2006 Load: 77.1 t ADT: 444

BRIDGE 3113 T-888

Good

Over: OVER SWAMP RUN

TIE LINE RD PINE TOWNSHIP, Mercer, PA

Built 1968 Load: 78.0 t ADT: 561

BRIDGE 2903 T-548

Good

Over: OVER LT. NESHANNOCK CK.B

NO. 8 RD. WILMINGTON TWP., Mercer, PA

Built 1956 Load: 83.5 t ADT: 132

SR 3032 CONNELY BL

Good

Over: OVER PINE RUN

CITY OF SHARON, Mercer, PA

Built 1989 Load: 88.9 t ADT: 7,324

SR 1011

Good

Over: PINE RUN

PERRY TOWNSHIP, Mercer, PA

Built 1907 Load: 88.9 t ADT: 431

SR 80 EB/WB & RAMP

Good

Over: HOGBACK RUN

SHENANGO TOWNSHIP, Mercer, PA

Built 1966 Load: 89.7 t ADT: 24,178

SOUTH OAKLAND

Good

Over: OVER US 62

SOUTH OAKLAND AVE SHARON, Mercer, PA

Built 2006 Load: 99.8 t ADT: 3,127

BRIDGE 2323

Good

Over: OVER HOGBACK RUN

HOGBACK RD. HERMITAGE, Mercer, PA

Mercer County Bridge Snapshot

Condition distribution

Mercer County's Poor-condition bridges carry 67,582 vehicle crossings a day

59.6% of Mercer County's bridges have passed the 50-year mark

One structure carries 14.5% of the county's Poor-condition bridge traffic

How Mercer 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 (438)

BRIDGE 2611 T-730

BRIDGE 112 T-374

BAKER HILL ROAD

BRIDGE 1218 T-703

SR 718 STATE ST

SUNOL ROAD

BRIDGE 1317 T-422

SR 3022 RUTLEDGE R

SR 4021 BEATTY SCH

BRIDGE 1315 T-589

SR 1004 Stoneboro

SR 4001 N SUMMIT

BRIDGE 2106

BRIDGE 3113 T-888

BRIDGE 2903 T-548

SR 3032 CONNELY BL

SR 1011

SR 80 EB/WB & RAMP

SOUTH OAKLAND

BRIDGE 2323

BRIDGE 803 OHL ST

BRIDGE 250 T-568

BRIDGE 2805 T-303

T-588 HURON STREET

TOWNSHIP ROAD 182

LEBANON AVE.

BRIDGE 1015 T-740

BRIDGE 2606 T-401

BRIDGE 1017 T-693

BRIDGE 124 T-480

BRIDGE 2329 WENGLE

BRIDGE 2350

BRIDGE 2108 T-784

SR 3022 RUTLEDGE R

SR 2014 SCRUBGRASS

BRIDGE 1606 T-661

BRIDGE 2107 T-784

SR 4021 ATLANTIC

BRIDGE 2007 T-688

SR 2017 N.FOSTER R

BRIDGE 199 T-301

SR 318 MAIN ST

SR 4021 CREEK RD

BRIDGE 3011 T-722

BRIDGE 1851

SR 2006 BLACKTOWN

SR 2014 SCRUBGRASS

T499 ORR ROAD

BRIDGE 2339 SERVIC

BRIDGE 2111 T-784

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