How many bridges are in South Dakota?

South Dakota has 5,887 public highway bridges tracked in the FHWA National Bridge Inventory. View detailed condition data for each bridge on PlainBridges.

What percentage of bridges in South Dakota are in Poor condition?

16.4% of bridge records in South Dakota are in Poor condition, meaning the lowest applicable major-component rating is 4 or below, compared with 7.5% across state inventories.

State profile · Above median Poor share

South Dakota bridge safety

Name: South Dakota public highway bridge inventory (FHWA NBI)
Creator: PlainBridges
License: https://creativecommons.org/publicdomain/zero/1.0/

According to the Federal Highway Administration's 2024 National Bridge Inventory, condition ratings, load ratings, and Poor-condition shares for every public highway bridge in South Dakota.

Compiled by PlainBridges

5,887
Public bridges: 33.8%
Good condition: 16.4%
Poor condition

South Dakota holds 5,887 public highway bridges (#33 of 52 by inventory) with a 16.36% Poor share (#3 of 52 by Poor share).

That is 16.4% of the state's inventory, against an average of 7.5% across the 54 states and territories with Poor-rated bridges on file, which places it 51 of 54 ordered from the lowest Poor share upward. A bridge is rated Poor when its weakest applicable component scores 4 or below on the inspecting agency's 0-9 scale, so the category is a maintenance and funding signal rather than a closure order or a live crossing-safety verdict.

Inventory: FHWA NBI 2024 · last ETL August 2026

Total Bridges

5,887

Public highway bridges in South Dakota

Good Condition

33.8%

1,992 bridges rated 7-9

-16.2pp vs 50% benchmark

Poor Condition

16.4%

963 bridges whose lowest applicable component is rated 0-4

8.8pp vs national avg 7.5%

South Dakota vs national bridge condition

South Dakota - Good condition share 33.8%

National avg

Share of bridges rated 7-9 on the FHWA 0-9 scale (deck, superstructure, substructure all good).

South Dakota - Poor-condition share 54.5%

National avg

Lower is better. Bar maxes at 30% (worst-state ceiling). National average sits at 7.5%.

Inventory size and Poor-condition share are different measures: South Dakota has 5,887 bridges and a 16.4% Poor-condition share in the 2024 NBI, rank #51 of 54 jurisdictions ordered from the lowest share upward. The dashed comparisons mark the national average state rate and the midpoint of the plotted inventory range; neither is a live safety or closure threshold.

South Dakota vs all states by public bridge inventory

Where this state's FHWA NBI public-highway bridge count sits among every state and territory on PlainBridges

5,887 33rd of 54 higher than 21 of 54 states

States and territories, banded by public bridge inventory size

Each bar is a band; taller bars hold more states. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.

Source FHWA National Bridge Inventory · 2024

Read the rank neighborhood for South Dakota

The highlighted point is South Dakota: 5,887 bridges and 16.36% in Poor condition, rank #51 of 54 jurisdictions ordered from the lowest share upward. The five jurisdictions immediately above and below South Dakota on that same Poor-share ordering:

Rhode Island: 783 bridges · 15.20% Poor
Maine: 2,518 bridges · 15.41% Poor
South Dakota: 5,887 bridges · 16.36% Poor
West Virginia: 7,348 bridges · 18.64% Poor
Iowa: 23,719 bridges · 19.16% Poor

The full national sortable table lives on the rankings page.

Material families in South Dakota

Exclusive FHWA material families across all 5,887 bridges in this state; continuous variants fold into the parent family. Orthogonal to the Poor-share scatter above.

Concrete 3,007 bridges (51%) Prestressed concrete 1,266 bridges (22%) Steel 1,402 bridges (24%) Wood or timber 194 bridges (3%) Other 18 bridges (0%)

Who maintains South Dakota’s inventory

State agency holds 31.3% of the 5,887 public highway bridges filed under South Dakota in the 2024 NBI, the agency-of-record split for this state, not a condition verdict.

State agency 1,842 bridges (31%) County agency 3,658 bridges (62%) Local agency 254 bridges (4%) Federal agency 132 bridges (2%) Other 1 bridges (0%)

When South Dakota’s bridges were built

Pre-1950 construction accounts for 18.2% of the 5,887 bridges with a recorded original year in South Dakota. Era bands are orthogonal to the Poor-share ranking above.

Pre-1950 1,073 bridges (18%) 1950–1979 2,272 bridges (39%) 1980–1999 1,144 bridges (19%) 2000+ 1,398 bridges (24%)

Condition Distribution

Bridge inventory deck-condition mix - South Dakota (FHWA NBI)

Counties (66)

Aurora 61 Beadle 152 Bennett 15 Bon Homme 126 Brookings 233 Brown 170 Brule 38 Buffalo 25 Butte 143 Campbell 15 Charles Mix 103 Clark 20 Clay 94 Codington 74 Corson 49 Custer 95 Davison 123 Day 34 Deuel 72 Dewey 28 Douglas 44 Edmunds 20 Fall River 80 Faulk 46 Grant 205 Gregory 51 Haakon 69 Hamlin 62 Hand 126 Hanson 62 Harding 49 Hughes 40 Hutchinson 161 Hyde 23 Jackson 89 Jerauld 35 Jones 37 Kingsbury 35 Lake 79 Lawrence 136 Lincoln 207 Lyman 114 Marshall 39 McCook 98 McPherson 14 Meade 215 Mellette 28 Miner 64 Minnehaha 393 Moody 87 Oglala Lakota 34 Pennington 348 Perkins 60 Potter 24 Roberts 157 Sanborn 53 Spink 176 Stanley 37 Sully 31 Todd 24 Tripp 90 Turner 143 Union 170 Walworth 33 Yankton 99 Ziebach 30

South Dakota vs nearby ranks

Adjacent states by Poor-condition share (lower share = better)

States are ranked by the share of bridges whose lowest applicable component rating is 4 or below. This describes recorded condition; it does not measure funding effectiveness or live crossing safety. States here sit immediately above and below South Dakota on the same metric.

Rhode Island

15.20% top marginal rate

Structure: Progressive
Burden @ $100K: $783

Maine

15.41% top marginal rate

Structure: Progressive
Burden @ $100K: $2,518

Selected

South Dakota

16.36% top marginal rate

Structure: Progressive
Burden @ $100K: $5,887

West Virginia

18.64% top marginal rate

Structure: Progressive
Burden @ $100K: $7,348

Iowa

19.16% top marginal rate

Structure: Progressive
Burden @ $100K: $23,719

Bridges Needing Most Attention in South Dakota

Six lowest-condition bridges in South Dakota, ranked by the portal's composite display score. Inspection intervals are risk-based under current NBIS rules.

South Dakota vs national bridge condition

Material families in South Dakota

Who maintains South Dakota’s inventory

When South Dakota’s bridges were built

Condition Distribution

Counties (66)

Bridges Needing Most Attention in South Dakota

SMITHWICK ROAD

395th Avenue

216 ST

200TH ST

412th Avenue

41480 299th Street

All Bridges in South Dakota

207TH ST

271 STREET

29280 431st Avenue

227 AVENUE

234TH STREET

29620 396th Avenue

42480 302nd Street

398TH AVENUE

294th Street

IDLEHURST LANE

39740 296th Street

172 STREET

454 AVENUE

142 STREET

117th Street

107th Street

475th Avenue

141st Street

405th Avenue

113th Street

279 STREET

427th Avenue

378 AVE

201st Street

29160 420th Avenue

180th Street

WHITEWOOD SERVICE

113th Street

221st Street

112th Street

465th Avenue

139th Street

155TH ST

382ND AVE

403RD AVE

265 ST

217th Street

211th Street

29600 426th Avenue

425th Avenue

242nd Street

TOWN STREET

40430 308th Street

29140 408th Avenue

137TH Street

485 AVENUE

318th Avenue

222 ST

168TH ST

112th Street

Related