Total bridges
157
Public highway bridges in Jefferson County
County profile · official public datasets
Jefferson County, IA
157 public highway bridges tracked in the FHWA National Bridge Inventory: 43.9% rated Good, 37.6% Fair, 18.5% Poor.
- 157
- Public bridges
- 43.9%
- Good condition
- 18.5%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Jefferson County posts a better-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.
- Top 47%
- lowest Poor share in state
- 18.5%
- Poor-condition share
- 157
- public highway bridges
- 1983
- 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.
Jefferson County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Jefferson County ranks #47 of 99 Iowa counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 18.5%). Jefferson County, Iowa contains 157 public highway bridges. Roughly 43.9% are rated “Good,” 37.6% “Fair,” and 18.5% “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.
Good condition
43.9%
69 of 157 rated 7-9
Fair condition
37.6%
59 of 157 rated 5-6
Poor condition
18.5%
29 of 157 rated 4 or below
In-state Poor-share rank
#47 of 99
Among Iowa counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 157 NBI-tracked bridges by lowest applicable component rating.
Good 43.9% (69)
Fair 37.6% (59)
Poor 18.5% (29)
Jefferson County's Poor-condition bridges carry 4,683 vehicle crossings a day
That is 4% of the county's reported daily bridge traffic on 18.5% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 161 crossings a day against 1,060 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 157 of 157 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
39.5% of Jefferson County's bridges have passed the 50-year mark
62 of the 157 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 43.9% 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 44.8% of the county's Poor-condition bridge traffic
E BURLINGTON AVE over WEST CROW CREEK, built 1954, carries 2,100 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 29-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 4,683 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Jefferson County's bridges were built
157 bridges with a recorded construction year, grouped by decade
- 1900s 4
1900–1909
4 bridges
- 1910s 2
1910–1919
2 bridges
- 1920s 3
1920–1929
3 bridges
- 1930s 1
1930–1939
1 bridges
- 1940s 2
1940–1949
2 bridges
- 1950s
1950–1959
26 bridges
- 1960s
1960–1969
14 bridges
- 1970s
1970–1979
18 bridges
- 1980s
1980–1989
16 bridges
- 1990s 8
1990–1999
8 bridges
- 2000s
2000–2009
30 bridges
- 2010s
2010–2019
28 bridges
- 2020s 5
2020–2029
5 bridges
What this shows Construction peaked in the 2000s, when 30 of the county's bridges still in the inventory were built, which is 19.1% of those with a recorded year. That cohort is now 15 to 24 years old in the 2024 inventory. Its average build year (1983) matches the Iowa average (1979).
How Jefferson County compares with Iowa's closest counties by inventory size
The 5 Iowa counties nearest Jefferson County in number of bridges, with their condition splits. Its 18.5% Poor share is the 3rd-lowest of these 6. Its average build year of 1983 against a peer-group mean of 1980 is in line with the group.
Showing the 5 closest of 98 Iowa counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Wayne County | 163 | 44.2% | 37.4% | 18.4% | 1989 |
| Monona County | 162 | 36.4% | 38.3% | 25.3% | 1973 |
| Jefferson County (this page) | 157 | 43.9% | 37.6% | 18.5% | 1983 |
| Buena Vista County | 156 | 35.9% | 32.7% | 31.4% | 1979 |
| Van Buren County | 156 | 23.7% | 44.9% | 31.4% | 1975 |
| Clay County | 151 | 35.8% | 54.3% | 9.9% | 1982 |
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 Jefferson 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 Jefferson County, both outside Iowa so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside IA (157 bridges here).
- Lowndes County, AL · 157 bridges
- Franklin County, MS · 157 bridges
- Washington County, MO · 157 bridges
- Stark County, ND · 157 bridges
Similar average build year
Nearest mean year-built outside IA (1983 here).
- Dallas County, TX · avg 1983 · 3,230 bridges
- Bexar County, TX · avg 1983 · 2,342 bridges
- Sedgwick County, KS · avg 1983 · 1,333 bridges
- Will County, IL · avg 1983 · 649 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
Fair-condition bridges (59)
US 34 EB
FairOver: CROW CREEK
0.8 mi. E of Jct. Iowa 1, Jefferson, IA
Built 2007 Load: 39.2 t ADT: 2,600
US 34 WB
FairOver: MITCHELL CREEK
3.6 mi. W of Jct. IA 1, Jefferson, IA
Built 2008 Load: 40.6 t ADT: 2,485
LOCAL
FairOver: SOUTH WALNUT CREEK
073093302, Jefferson, IA
Built 1986 Load: 42.6 t ADT: 15
SPRUCE AVE
FairOver: ROCK BRANCH
073083101, Jefferson, IA
Built 1950 Load: 43.4 t ADT: 50
FM
FairOver: BRUSH CREEK
072091505, Jefferson, IA
Built 1988 Load: 44.4 t ADT: 200
US 34 WB
FairOver: CHURCH CREEK
2.3 mi. E of Jct. SR V63, Jefferson, IA
Built 2007 Load: 46.6 t ADT: 3,900
LOCAL
FairOver: STREAM
071102904, Jefferson, IA
Built 1968 Load: 53.2 t ADT: 60
FM
FairOver: CREEK
073081902, Jefferson, IA
Built 1950 Load: 55.6 t ADT: 50
FM
FairOver: CREEK
072081502, Jefferson, IA
Built 1971 Load: 99.9 t ADT: 330
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.