Total bridges
13
Public highway bridges in Logan County
County profile · official public datasets
Logan County, ND
13 public highway bridges tracked in the FHWA National Bridge Inventory: 61.5% rated Good, 23.1% Fair, 15.4% Poor.
- 13
- Public bridges
- 61.5%
- Good condition
- 15.4%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Logan County posts a higher-than-median Poor-condition share among rated counties in the state across rated county bridge inventory.
- 39th
- of 53 on Poor share
- 15.4%
- Poor-condition share
- 13
- public highway bridges
- 1973
- 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.
Logan County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Logan County ranks #39 of 53 North Dakota counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 15.4%). Logan County, North Dakota contains 13 public highway bridges. Roughly 61.5% are rated “Good,” 23.1% “Fair,” and 15.4% “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
61.5%
8 of 13 rated 7-9
Fair condition
23.1%
3 of 13 rated 5-6
Poor condition
15.4%
2 of 13 rated 4 or below
In-state Poor-share rank
#39 of 53
Among North Dakota counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 13 NBI-tracked bridges by lowest applicable component rating.
Good 61.5% (8)
Fair 23.1% (3)
Poor 15.4% (2)
Logan County's Poor-condition bridges carry 29 vehicle crossings a day
That is 1.8% of the county's reported daily bridge traffic on 15.4% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 15 crossings a day against 131 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 13 of 13 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
46.2% of Logan County's bridges have passed the 50-year mark
6 of the 13 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 61.5% 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 82.8% of the county's Poor-condition bridge traffic
77th St SE over CREEK, built 1939, carries 24 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 2-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 29 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Logan County's bridges were built
13 bridges with a recorded construction year, grouped by decade
- 1930s 1
1930–1939
1 bridges
- 1940s
1940–1949
2 bridges
- 1950s 1
1950–1959
1 bridges
- 1960s
1960–1969
2 bridges
- 1980s
1980–1989
5 bridges
- 1990s 1
1990–1999
1 bridges
- 2010s 1
2010–2019
1 bridges
What this shows Construction peaked in the 1980s, when 5 of the county's bridges still in the inventory were built, which is 38.5% of those with a recorded year. That cohort is now 35 to 44 years old in the 2024 inventory. Its average build year (1973) matches the North Dakota average (1975).
How Logan County compares with North Dakota's closest counties by inventory size
The 5 North Dakota counties nearest Logan County in number of bridges, with their condition splits. Its 15.4% Poor share is the 6th-lowest of these 6. Its average build year of 1973 against a peer-group mean of 1971 is in line with the group.
Showing the 5 closest of 52 North Dakota counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Rolette County | 18 | 66.7% | 33.3% | 0% | 1971 |
| Divide County | 13 | 30.8% | 61.5% | 7.7% | 1975 |
| Logan County (this page) | 13 | 61.5% | 23.1% | 15.4% | 1973 |
| McIntosh County | 11 | 45.5% | 45.5% | 9.1% | 1973 |
| Kidder County | 10 | 10% | 90% | 0% | 1962 |
| Sheridan County | 8 | 87.5% | 12.5% | 0% | 1974 |
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 Logan 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 Logan County, both outside North Dakota so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside ND (13 bridges here).
- Bethel County, AK · 13 bridges
- San Juan County, CO · 13 bridges
- Perkins County, NE · 13 bridges
- Wheeler County, NE · 13 bridges
Similar average build year
Nearest mean year-built outside ND (1973 here).
- Jefferson County, AL · avg 1973 · 1,068 bridges
- Erie County, NY · avg 1973 · 906 bridges
- Davidson County, TN · avg 1973 · 832 bridges
- Lancaster County, PA · avg 1973 · 801 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
Poor-condition bridges (2)
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.