Total bridges
15
Public highway bridges in Bennett County
County profile · official public datasets
Bennett County, SD
15 public highway bridges tracked in the FHWA National Bridge Inventory: 26.7% rated Good, 53.3% Fair, 20% Poor.
- 15
- Public bridges
- 26.7%
- Good condition
- 20%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Bennett County pairs a higher-than-median Poor-condition share among rated counties in the state with an older average build year than the state inventory.
- 46th
- of 66 on Poor share
- 20%
- Poor-condition share
- 15
- public highway bridges
- 1962
- 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.
Bennett County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Bennett County ranks #46 of 66 South Dakota counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 20%). Bennett County, South Dakota contains 15 public highway bridges. Roughly 26.7% are rated “Good,” 53.3% “Fair,” and 20% “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
26.7%
4 of 15 rated 7-9
Fair condition
53.3%
8 of 15 rated 5-6
Poor condition
20%
3 of 15 rated 4 or below
In-state Poor-share rank
#46 of 66
Among South Dakota counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 15 NBI-tracked bridges by lowest applicable component rating.
Good 26.7% (4)
Fair 53.3% (8)
Poor 20% (3)
Bennett County's Poor-condition bridges carry 104 vehicle crossings a day
That is 2.9% of the county's reported daily bridge traffic on 20% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 35 crossings a day against 253 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 15 of 15 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
80% of Bennett County's bridges have passed the 50-year mark
12 of the 15 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 26.7% 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 38.5% of the county's Poor-condition bridge traffic
220 AVENUE over LAKE CK, built 1950, carries 40 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 3-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 104 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Bennett County's bridges were built
15 bridges with a recorded construction year, grouped by decade
- 1930s
1930–1939
3 bridges
- 1950s
1950–1959
6 bridges
- 1960s
1960–1969
3 bridges
- 1970s 1
1970–1979
1 bridges
- 2010s 1
2010–2019
1 bridges
- 2020s 1
2020–2029
1 bridges
What this shows Construction peaked in the 1950s, when 6 of the county's bridges still in the inventory were built, which is 40% of those with a recorded year. That cohort is now 65 to 74 years old in the 2024 inventory. Its average build year is 1962, 13 years older than the South Dakota average of 1975.
How Bennett County compares with South Dakota's closest counties by inventory size
The 5 South Dakota counties nearest Bennett County in number of bridges, with their condition splits. Its 20% Poor share is the 4th-lowest of these 6. Its average build year of 1962 against a peer-group mean of 1982 is 20 years older.
Showing the 5 closest of 65 South Dakota counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Hyde County | 23 | 34.8% | 39.1% | 26.1% | 1974 |
| Clark County | 20 | 60% | 40% | 0% | 1987 |
| Edmunds County | 20 | 35% | 40% | 25% | 1991 |
| Campbell County | 15 | 46.7% | 53.3% | 0% | 1978 |
| Bennett County (this page) | 15 | 26.7% | 53.3% | 20% | 1962 |
| McPherson County | 14 | 35.7% | 64.3% | 0% | 1978 |
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 Bennett 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 Bennett County, both outside South Dakota so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside SD (15 bridges here).
- Yakutat City and County, AK · 15 bridges
- Antrim County, MI · 15 bridges
- Kalkaska County, MI · 15 bridges
- Oscoda County, MI · 15 bridges
Similar average build year
Nearest mean year-built outside SD (1962 here).
- Berks County, PA · avg 1962 · 667 bridges
- Pecos County, TX · avg 1962 · 470 bridges
- Bristol County, MA · avg 1962 · 384 bridges
- Norfolk County, MA · avg 1962 · 343 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
All bridges (15)
220 AVENUE
FairOver: BEAR IN THE LODGE CK
5.8N 1.8E MARTIN, Bennett, SD
Built 1958 Load: 18.8 t ADT: 40
231 AVENUE
FairOver: LAKE CK
0.5 S TUTHILL, Bennett, SD
Built 1954 Load: 20.0 t ADT: 120
220 AVENUE
FairOver: BEAR IN THE LODGE CK
13.4N 1.4E MARTIN, Bennett, SD
Built 1963 Load: 22.6 t ADT: 40
SD073
FairOver: LITTLE WHITE RV
3 S OF MARTIN, Bennett, SD
Built 1964 Load: 23.3 t ADT: 523
231 AVENUE
FairOver: CK
2.3 N TUTHILL, Bennett, SD
Built 1954 Load: 24.5 t ADT: 123
231 AVENUE
FairOver: LITTLE WHITE RV
1.3 N TUTHILL, Bennett, SD
Built 1976 Load: 27.1 t ADT: 119
SD073
FairOver: LAKE CK
6.3 S JCT US 18, Bennett, SD
Built 1964 Load: 38.9 t ADT: 523
US018
FairOver: CK
3.8 E OGLALA LAKOTA CO LN, Bennett, SD
Built 1951 Load: 42.4 t ADT: 963
AUTO TOUR ROAD
GoodOver: LAKE CREEK
DIKE 8-SCT 16-S OF OFFICE, Bennett, SD
Built 1936 Load: 5.4 t ADT: 15
290 STREET
GoodOver: CK
3 N 0.5 W TUTHILL, Bennett, SD
Built 1954 Load: 24.5 t ADT: 123
IRR BIA RTE ALLEN
GoodOver: TRIB OF WHITE RIVER
EAST OF ALLEN, Bennett, SD
Built 2017 Load: 32.6 t ADT: 300
US018
GoodOver: TRIB LITTLE WHITE RV
0.5W Todd Co Border US18, Bennett, SD
Built 2020 Load: 95.5 t ADT: 573
220 AVENUE
PoorOver: LAKE CK
1.2E 6.3S MARTIN, Bennett, SD
Built 1950 Load: 12.7 t ADT: 40
295 STREET
PoorOver: CK
14.5W 3.0S MARTIN, Bennett, SD
Built 1932 Load: 18.3 t ADT: 27
205 AVENUE
PoorOver: CK
13.0W 2.8S MARTIN, Bennett, SD
Built 1932 Load: 18.3 t ADT: 37
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.