Total bridges
99
Public highway bridges in Yankton County
County profile · official public datasets
Yankton County, SD
99 public highway bridges tracked in the FHWA National Bridge Inventory: 41.4% rated Good, 43.4% Fair, 15.2% Poor.
- 99
- Public bridges
- 41.4%
- Good condition
- 15.2%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Yankton County pairs a better-than-median Poor-condition share among rated counties in the state with a newer average build year than the state inventory.
- Top 50%
- lowest Poor share in state
- 15.2%
- Poor-condition share
- 99
- 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.
Yankton County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Yankton County ranks #33 of 66 South Dakota counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 15.2%). Yankton County, South Dakota contains 99 public highway bridges. Roughly 41.4% are rated “Good,” 43.4% “Fair,” and 15.2% “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
41.4%
41 of 99 rated 7-9
Fair condition
43.4%
43 of 99 rated 5-6
Poor condition
15.2%
15 of 99 rated 4 or below
In-state Poor-share rank
#33 of 66
Among South Dakota counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 99 NBI-tracked bridges by lowest applicable component rating.
Good 41.4% (41)
Fair 43.4% (43)
Poor 15.2% (15)
Yankton County's Poor-condition bridges carry 5,787 vehicle crossings a day
That is 5.4% of the county's reported daily bridge traffic on 15.2% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 386 crossings a day against 1,133 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 99 of 99 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
36.4% of Yankton County's bridges have passed the 50-year mark
36 of the 99 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 41.4% 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 68.8% of the county's Poor-condition bridge traffic
W 23RD STREET over MARNE CREEK, built 1976, carries 3,980 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 15-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 5,787 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Yankton County's bridges were built
99 bridges with a recorded construction year, grouped by decade
- 1930s
1930–1939
6 bridges
- 1940s
1940–1949
12 bridges
- 1950s
1950–1959
11 bridges
- 1960s 3
1960–1969
3 bridges
- 1970s
1970–1979
9 bridges
- 1980s
1980–1989
13 bridges
- 1990s
1990–1999
13 bridges
- 2000s
2000–2009
11 bridges
- 2010s
2010–2019
11 bridges
- 2020s
2020–2029
10 bridges
What this shows Construction peaked in the 1980s, when 13 of the county's bridges still in the inventory were built, which is 13.1% of those with a recorded year. That cohort is now 35 to 44 years old in the 2024 inventory. Its average build year is 1983, 8 years newer than the South Dakota average of 1975.
How Yankton County compares with South Dakota's closest counties by inventory size
The 5 South Dakota counties nearest Yankton County in number of bridges, with their condition splits. Its 15.2% Poor share is the 3rd-lowest of these 6. Its average build year of 1983 against a peer-group mean of 1977 is 6 years newer.
Showing the 5 closest of 65 South Dakota counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Charles Mix County | 103 | 38.8% | 37.9% | 23.3% | 1971 |
| Yankton County (this page) | 99 | 41.4% | 43.4% | 15.2% | 1983 |
| McCook County | 98 | 44.9% | 44.9% | 10.2% | 1977 |
| Custer County | 95 | 46.3% | 48.4% | 5.3% | 1977 |
| Clay County | 94 | 58.5% | 25.5% | 16% | 1985 |
| Tripp County | 90 | 27.8% | 44.4% | 27.8% | 1975 |
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 Yankton 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 Yankton County, both outside South Dakota so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside SD (99 bridges here).
- Washington County, FL · 99 bridges
- Crisp County, GA · 99 bridges
- Harris County, GA · 99 bridges
- Newton County, GA · 99 bridges
Similar average build year
Nearest mean year-built outside SD (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.
Poor-condition bridges (15)
29280 431st Avenue
PoorOver: James River
7.2N & 1E of Lesterville, Yankton, SD
Built 1959 Load: 4.9 t ADT: 315
44820 304 ST
PoorOver: Tributary to Clay Creek
4N&2.2E Mission Hill, Yankton, SD
Built 1940 Load: 7.1 t ADT: 45
45190 299 ST
PoorOver: Trib. to Turkey Creek
2 S & 0.1 W Irene, Yankton, SD
Built 1940 Load: 7.9 t ADT: 5
44960 296 ST
PoorOver: Turkey Creek
2.4 W 1.0 N Irene, Yankton, SD
Built 1979 Load: 12.2 t ADT: 75
43160 307th Street
PoorOver: Marne Creek
3S & 3.4W of Utica, Yankton, SD
Built 1930 Load: 14.6 t ADT: 10
CEDAR STREET
PoorOver: MARNE CREEK
CEDAR STREET - YANKTON, Yankton, SD
Built 1978 Load: 14.7 t ADT: 969
30680 432nd Avenue
PoorOver: Marne Creek
3W & 2.8S of Utica, Yankton, SD
Built 1940 Load: 15.9 t ADT: 10
W 23RD STREET
PoorOver: MARNE CREEK
W 23RD STREET - YANKTON, Yankton, SD
Built 1976 Load: 16.1 t ADT: 3,980
44660 298th Street
PoorOver: Trib. to Clay Creek
5.4W & 1S of Irene, Yankton, SD
Built 1940 Load: 17.1 t ADT: 25
43230 NW Jim River
PoorOver: Trib. to James River
6.7N & 2.3E Lesterville, Yankton, SD
Built 1975 Load: 18.3 t ADT: 50
30730 436th Avenue
PoorOver: Marne Creek
3.3S & 1E of Utica, Yankton, SD
Built 1935 Load: 18.3 t ADT: 33
29250 442nd Avenue
PoorOver: Clay Creek
4.5N & 10W of Irene, Yankton, SD
Built 1930 Load: 18.3 t ADT: 50
30430 446th Avenue
PoorOver: Unnamed Creek
1.7N & 5W of Volin, Yankton, SD
Built 1941 Load: 18.3 t ADT: 100
44930 295 ST
PoorOver: Turkey Creek
2 N & 2.7 W Irene, Yankton, SD
Built 1991 Load: 19.6 t ADT: 75
45170 313 ST
PoorOver: Unnamed Creek
7 S & 0.7 E Volin, Yankton, SD
Built 1940 Load: 24.5 t ADT: 45
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.