Total bridges
34
Public highway bridges in Niobrara County
County profile · official public datasets
Niobrara County, WY
34 public highway bridges tracked in the FHWA National Bridge Inventory: 44.1% rated Good, 52.9% Fair, 2.9% Poor.
- 34
- Public bridges
- 44.1%
- Good condition
- 2.9%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Niobrara County pairs a top-quartile lowest Poor-condition share among rated counties in the state with a newer average build year than the state inventory.
- Top 22%
- lowest Poor share in state
- 2.9%
- Poor-condition share
- 34
- public highway bridges
- 1988
- 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.
Niobrara County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Niobrara County ranks #5 of 23 Wyoming counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 2.9%). Niobrara County, Wyoming contains 34 public highway bridges. Roughly 44.1% are rated “Good,” 52.9% “Fair,” and 2.9% “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
44.1%
15 of 34 rated 7-9
Fair condition
52.9%
18 of 34 rated 5-6
Poor condition
2.9%
1 of 34 rated 4 or below
In-state Poor-share rank
#5 of 23
Among Wyoming counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 34 NBI-tracked bridges by lowest applicable component rating.
Good 44.1% (15)
Fair 52.9% (18)
Poor 2.9% (1)
Niobrara County's Poor-condition bridges carry 5 vehicle crossings a day
That is 0% of the county's reported daily bridge traffic on 2.9% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 5 crossings a day against 636 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 34 of 34 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
17.6% of Niobrara County's bridges have passed the 50-year mark
6 of the 34 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 44.1% 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 100% of the county's Poor-condition bridge traffic
Ni Cnty Rd 9 over Cheyenne River, built 1920, carries 5 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 1-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 5 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Niobrara County's bridges were built
34 bridges with a recorded construction year, grouped by decade
- 1920s 1
1920–1929
1 bridges
- 1950s 2
1950–1959
2 bridges
- 1960s 1
1960–1969
1 bridges
- 1970s 2
1970–1979
2 bridges
- 1980s
1980–1989
10 bridges
- 1990s
1990–1999
10 bridges
- 2000s
2000–2009
5 bridges
- 2010s 3
2010–2019
3 bridges
What this shows Construction peaked in the 1980s, when 10 of the county's bridges still in the inventory were built, which is 29.4% of those with a recorded year. That cohort is now 35 to 44 years old in the 2024 inventory. Its average build year is 1988, 12 years newer than the Wyoming average of 1976.
How Niobrara County compares with Wyoming's closest counties by inventory size
The 5 Wyoming counties nearest Niobrara County in number of bridges, with their condition splits. Its 2.9% Poor share is the 1st-lowest of these 6. Its average build year of 1988 against a peer-group mean of 1975 is 13 years newer.
Showing the 5 closest of 22 Wyoming counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Goshen County | 106 | 19.8% | 76.4% | 3.8% | 1974 |
| Big Horn County | 91 | 25.3% | 67% | 7.7% | 1972 |
| Washakie County | 61 | 41% | 49.2% | 9.8% | 1979 |
| Weston County | 43 | 25.6% | 65.1% | 9.3% | 1978 |
| Hot Springs County | 39 | 25.6% | 69.2% | 5.1% | 1974 |
| Niobrara County (this page) | 34 | 44.1% | 52.9% | 2.9% | 1988 |
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 Niobrara 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 Niobrara County, both outside Wyoming so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside WY (34 bridges here).
- Bear Lake County, ID · 34 bridges
- Plaquemines County, LA · 34 bridges
- Golden Valley County, ND · 34 bridges
- Guayanilla County, PR · 34 bridges
Similar average build year
Nearest mean year-built outside WY (1988 here).
- Travis County, TX · avg 1988 · 1,544 bridges
- Grant County, OK · avg 1988 · 476 bridges
- Loudoun County, VA · avg 1988 · 442 bridges
- Licking County, OH · avg 1988 · 439 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
Poor-condition bridges (1)
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.