County profile · official public datasets

Minnehaha County, SD

393 public highway bridges tracked in the FHWA National Bridge Inventory: 40.5% rated Good, 50.1% Fair, 9.4% Poor.

393
Public bridges: 40.5%
Good condition: 9.4%
Poor condition

The verdict

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

Minnehaha 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 27%
lowest Poor share in state: 9.4%
Poor-condition share: 393
public highway bridges: 1985
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.

Minnehaha County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Minnehaha County ranks #18 of 66 South Dakota counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 9.4%). Minnehaha County, South Dakota contains 393 public highway bridges. Roughly 40.5% are rated “Good,” 50.1% “Fair,” and 9.4% “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.

Total bridges

393

Public highway bridges in Minnehaha County

Good condition

40.5%

159 of 393 rated 7-9

Fair condition

50.1%

197 of 393 rated 5-6

Poor condition

9.4%

37 of 393 rated 4 or below

In-state Poor-share rank

#18 of 66

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

Condition distribution

Share of 393 NBI-tracked bridges by lowest applicable component rating.

Good

40.5% (159)

Fair

50.1% (197)

Poor

9.4% (37)

Minnehaha County's Poor-condition bridges carry 63,801 vehicle crossings a day

That is 2.9% of the county's reported daily bridge traffic on 9.5% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 1,724 crossings a day against 4,711 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 391 of 393 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

33.3% of Minnehaha County's bridges have passed the 50-year mark

131 of the 393 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 40.5% 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 21.6% of the county's Poor-condition bridge traffic

49th Street over Big Sioux River, built 1979, carries 13,800 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 37-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 63,801 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1900s

1
1910s

1
1920s

1
1930s

18
1940s

14
1950s

28
1960s

53
1970s

33
1980s

46
1990s

75
2000s

56
2010s

54
2020s

13

What this shows Construction peaked in the 1990s, when 75 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 25 to 34 years old in the 2024 inventory. Its average build year is 1985, 10 years newer than the South Dakota average of 1975.

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

The 5 South Dakota counties nearest Minnehaha County in number of bridges, with their condition splits. Its 9.4% Poor share is the 2nd-lowest of these 6. Its average build year of 1985 against a peer-group mean of 1976 is 9 years newer.

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

Bridge inventory size and condition shares for Minnehaha County and the 5 South Dakota counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Minnehaha County (this page)	393	40.5%	50.1%	9.4%	1985
Pennington County	348	30.2%	62.4%	7.5%	1976
Brookings County	233	26.6%	50.6%	22.7%	1973
Meade County	215	43.7%	45.6%	10.7%	1979
Lincoln County	207	34.3%	48.3%	17.4%	1973
Grant County	205	35.1%	48.8%	16.1%	1980

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

Similar inventory size

Nearest county inventories outside SD (393 bridges here).

Gage County, NE · 394 bridges
DeKalb County, GA · 392 bridges
Ulster County, NY · 392 bridges
Essex County, MA · 395 bridges

Similar average build year

Nearest mean year-built outside SD (1985 here).

Hillsborough County, FL · avg 1985 · 840 bridges
Lancaster County, NE · avg 1985 · 661 bridges
Nueces County, TX · avg 1985 · 528 bridges
Grayson County, TX · avg 1985 · 513 bridges

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

All 393 Good 159 Fair 197 Poor 37

Good-condition bridges (159)

Sort:

Minnehaha County Bridge Snapshot

Condition distribution

Minnehaha County's Poor-condition bridges carry 63,801 vehicle crossings a day

33.3% of Minnehaha County's bridges have passed the 50-year mark

One structure carries 21.6% of the county's Poor-condition bridge traffic

How Minnehaha 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

Good-condition bridges (159)

459TH AVENUE

478TH AVE HWY 121

Maple Street

SD019

Minnesota Avenue

SD011

N. Bahnson Avenue

N. Career Avenue

I029 NF

West 12th Street

26th Street

252ND ST HWY 118

250TH ST HWY 114

250TH STREET

I090 E

SD011

W 60TH ST N

461ST AVE HWY 155

249TH STREET

250TH ST HWY 114

SD100

SD100

West 12th Street

474TH AVENUE

I090 W

478TH AVE HWY 121

Yankton Trails Prk

SD115

I229 S

478 AVE (FAS 1157)

I029 S

I029 N

SD115

57th Street

E 60TH ST N

266TH ST HWY 146

258TH ST HWY 130

257TH STREET

264TH STREET

I229 S

I229 N

264TH STREET

SD115

254TH ST HWY 122

W MAPLE ST

245TH ST / 15TH ST

WESTERN AVE

I090 W

SD115

60TH ST N

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