Total bridges
299
Public highway bridges in Northumberland County
County profile · official public datasets
Northumberland County, PA
299 public highway bridges tracked in the FHWA National Bridge Inventory: 41.8% rated Good, 51.5% Fair, 6.7% Poor.
- 299
- Public bridges
- 41.8%
- Good condition
- 6.7%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Northumberland County pairs a top-quartile lowest Poor-condition share among rated counties in the state with an older average build year than the state inventory.
- Top 13%
- lowest Poor share in state
- 6.7%
- Poor-condition share
- 299
- public highway bridges
- 1963
- 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.
Northumberland County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Northumberland County ranks #9 of 67 Pennsylvania counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 6.7%). Northumberland County, Pennsylvania contains 299 public highway bridges. Roughly 41.8% are rated “Good,” 51.5% “Fair,” and 6.7% “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.
Good condition
41.8%
125 of 299 rated 7-9
Fair condition
51.5%
154 of 299 rated 5-6
Poor condition
6.7%
20 of 299 rated 4 or below
In-state Poor-share rank
#9 of 67
Among Pennsylvania counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 299 NBI-tracked bridges by lowest applicable component rating.
Good 41.8% (125)
Fair 51.5% (154)
Poor 6.7% (20)
Northumberland County's Poor-condition bridges carry 13,433 vehicle crossings a day
That is 1.5% of the county's reported daily bridge traffic on 6.1% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 746 crossings a day against 3,439 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 297 of 299 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
63.5% of Northumberland County's bridges have passed the 50-year mark
190 of the 299 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 62.5% of the county's Poor-condition bridge traffic
W WALNUT ST over SHAMOKIN CREEK, built 1914, carries 8,400 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 20-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 13,433 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Northumberland County's bridges were built
299 bridges with a recorded construction year, grouped by decade
- pre-1900 12
Built before 1900
12 bridges
- 1900s 12
1900–1909
12 bridges
- 1910s 11
1910–1919
11 bridges
- 1920s 15
1920–1929
15 bridges
- 1930s
1930–1939
35 bridges
- 1940s
1940–1949
23 bridges
- 1950s
1950–1959
21 bridges
- 1960s
1960–1969
25 bridges
- 1970s
1970–1979
39 bridges
- 1980s
1980–1989
25 bridges
- 1990s
1990–1999
29 bridges
- 2000s
2000–2009
19 bridges
- 2010s
2010–2019
29 bridges
- 2020s 4
2020–2029
4 bridges
What this shows Construction peaked in the 1970s, when 39 of the county's bridges still in the inventory were built, which is 13% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year is 1963, 7 years older than the Pennsylvania average of 1970.
How Northumberland County compares with Pennsylvania's closest counties by inventory size
The 5 Pennsylvania counties nearest Northumberland County in number of bridges, with their condition splits. Its 6.7% Poor share is the 1st-lowest of these 6. Its average build year of 1963 against a peer-group mean of 1969 is 6 years older.
Showing the 5 closest of 66 Pennsylvania counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Greene County | 306 | 37.3% | 46.7% | 16% | 1967 |
| Indiana County | 301 | 29.9% | 51.2% | 18.9% | 1972 |
| Beaver County | 299 | 41.1% | 48.8% | 10% | 1972 |
| Northumberland County (this page) | 299 | 41.8% | 51.5% | 6.7% | 1963 |
| Franklin County | 294 | 29.6% | 62.2% | 8.2% | 1964 |
| Clearfield County | 292 | 38.4% | 47.6% | 14% | 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 Northumberland 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 Northumberland County, both outside Pennsylvania so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside PA (299 bridges here).
- Ada County, ID · 299 bridges
- DeKalb County, AL · 300 bridges
- Christian County, KY · 300 bridges
- Washington County, MD · 300 bridges
Similar average build year
Nearest mean year-built outside PA (1963 here).
- Worcester County, MA · avg 1963 · 1,014 bridges
- Honolulu County, HI · avg 1963 · 682 bridges
- Essex County, NJ · avg 1963 · 505 bridges
- Passaic County, NJ · avg 1963 · 333 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
Fair-condition bridges (154)
SR 2005
FairOver: OVER LOGAN RUN
5 MI S.OF RIVERSIDE BORO., Northumberland, PA
Built 1930 Load: 69.9 t ADT: 172
SR 2046
FairOver: OVER MAHANOY CREEK
2 MI SW OF GOWAN CITY, Northumberland, PA
Built 1915 Load: 72.6 t ADT: 114
SR 1011
FairOver: WARRIOR RUN
1 MI N OF TURBOTVILLE, Northumberland, PA
Built 1921 Load: 81.6 t ADT: 411
SR 1014
FairOver: W. B. SUSQUEHANNA RIVER
WATSONTOWN BORO RIVER BR., Northumberland, PA
Built 1927 Load: 99.8 t ADT: 3,765
Read our methodology - how this data is sourced, computed, and verified.
Related
Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainBridges
Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.