County profile · official public datasets

Jackson County, SD

89 public highway bridges tracked in the FHWA National Bridge Inventory: 29.2% rated Good, 55.1% Fair, 15.7% Poor.

89
Public bridges: 29.2%
Good condition: 15.7%
Poor condition

The verdict

According to the Federal Highway Administration's 2024 National Bridge Inventory.

Jackson 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.

34th
of 66 on Poor share: 15.7%
Poor-condition share: 89
public highway bridges: 1969
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.

Jackson County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Jackson County ranks #34 of 66 South Dakota counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 15.7%). Jackson County, South Dakota contains 89 public highway bridges. Roughly 29.2% are rated “Good,” 55.1% “Fair,” and 15.7% “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.

Total bridges

Public highway bridges in Jackson County

Good condition

29.2%

26 of 89 rated 7-9

Fair condition

55.1%

49 of 89 rated 5-6

Poor condition

15.7%

14 of 89 rated 4 or below

In-state Poor-share rank

#34 of 66

Among South Dakota counties with 5+ bridges, lower share ranks better

Condition distribution

Share of 89 NBI-tracked bridges by lowest applicable component rating.

Good

29.2% (26)

Fair

55.1% (49)

Poor

15.7% (14)

Jackson County's Poor-condition bridges carry 1,568 vehicle crossings a day

That is 1.2% of the county's reported daily bridge traffic on 15.7% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 112 crossings a day against 1,290 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 89 of 89 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

70.8% of Jackson County's bridges have passed the 50-year mark

63 of the 89 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 29.2% 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 83.8% of the county's Poor-condition bridge traffic

IRR BIA RTE 2 over POTATO CREEK, built 1942, carries 1,314 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 14-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 1,568 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1930s

7
1940s

9
1950s

12
1960s

30
1970s

7
1980s

6
1990s

9
2000s

3
2010s

4
2020s

2

What this shows Construction peaked in the 1960s, when 30 of the county's bridges still in the inventory were built, which is 33.7% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year is 1969, 6 years older than the South Dakota average of 1975.

How Jackson County compares with South Dakota's closest counties by inventory size

The 5 South Dakota counties nearest Jackson County in number of bridges, with their condition splits. Its 15.7% Poor share is the 3rd-lowest of these 6. Its average build year of 1969 against a peer-group mean of 1977 is 8 years older.

Showing the 5 closest of 65 South Dakota counties eligible for comparison.

Bridge inventory size and condition shares for Jackson County and the 5 South Dakota counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
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
Jackson County (this page)	89	29.2%	55.1%	15.7%	1969
Moody County	87	29.9%	46%	24.1%	1973

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 Jackson 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 Jackson County, both outside South Dakota so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside SD (89 bridges here).

Menard County, IL · 89 bridges
Wabash County, IL · 89 bridges
Noble County, IN · 89 bridges
Bath County, KY · 89 bridges

Similar average build year

Nearest mean year-built outside SD (1969 here).

Cook County, IL · avg 1969 · 1,721 bridges
Fresno County, CA · avg 1969 · 916 bridges
Cuyahoga County, OH · avg 1969 · 871 bridges
Ventura County, CA · avg 1969 · 501 bridges

Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.

All 89 Good 26 Fair 49 Poor 14

All bridges (89)

Sort:

Jackson County Bridge Snapshot

Condition distribution

Jackson County's Poor-condition bridges carry 1,568 vehicle crossings a day

70.8% of Jackson County's bridges have passed the 50-year mark

One structure carries 83.8% of the county's Poor-condition bridge traffic

How Jackson County compares with South Dakota's closest counties by inventory size

Nationwide counties with similar inventory size or average build year

Similar inventory size

Similar average build year

All bridges (89)

COTTONWOOD ROAD

237 STREET

Old NE Road

US014

IRR SD073

SD248

SD248

SD044

GRINDSTONE ROAD

FAIRVIEW ROAD

LONG VALLEY ROAD

IRR SD073

IRR SD063

SD240

I090 W

I090 E

I090 W

I090 W

I090 E

I090 W

I090 E

SD240

SD377

I090 E

US014

IRR SD044

I090 W

I090 E

I090 W

I090 E

I090 E

I090 W

I090 E

I090 W

I090 E

I090 W

I090 E

US014

I090 E

I090 W

I090 E

I090 W

IRR SD073

SD073

SD073

US014

I090

SD248

SWIFT HORSE ROAD

RED STONE ROAD

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