State profile · Above national median SD

South Dakota bridge safety

Condition ratings, load ratings, and structural-deficiency data for every public highway bridge in South Dakota — drawn straight from the FHWA National Bridge Inventory.

5,905
Public bridges
31.9%
Good condition
16.2%
Poor condition
16.2%
Structurally deficient

Total Bridges

5,905

Public highway bridges in South Dakota

Good Condition

31.9%

1,885 bridges rated 7-9

-18.1pp vs 50% benchmark

Poor Condition

16.2%

959 bridges rated 0-4

Structurally Deficient

16.2%

959 bridges flagged for repair priority

9.2pp vs national avg 7.0%

South Dakota vs national bridge condition

South Dakota — Good condition share 31.9%
National avg

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

South Dakota — Structurally deficient share 54.1%
National avg

Lower is better. Bar maxes at 30% (worst-state ceiling). National average sits at 7.0%.

Condition Distribution

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

South Dakota31.922099915325997%44.06435224386113%16.240474174428453%16.240474174428453%GoodFairPoorStructurally Deficient
Bridge inventory deck-condition mix — South Dakota (FHWA NBI)

Counties (66)

Aurora 61 Beadle 153 Bennett 15 Bon Homme 126 Brookings 234 Brown 170 Brule 38 Buffalo 25 Butte 143 Campbell 15 Charles Mix 103 Clark 21 Clay 94 Codington 74 Corson 49 Custer 95 Davison 125 Day 37 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 41 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 217 Mellette 28 Miner 64 Minnehaha 395 Moody 87 Oglala Lakota 34 Pennington 350 Perkins 60 Potter 24 Roberts 157 Sanborn 53 Spink 176 Stanley 37 Sully 31 Todd 24 Tripp 90 Turner 143 Union 172 Walworth 34 Yankton 99 Ziebach 30

South Dakota vs nearby ranks

Adjacent states on the structurally deficient leaderboard (lower share = better)

States are ranked by share of bridges flagged structurally deficient — the FHWA classification for any span where deck, superstructure, or substructure carries a condition rating of 4 or below. Lower percentages indicate stronger maintenance funding and inspection follow-through. States here sit immediately above and below South Dakota on the same metric.

66

Guam

15.25% top marginal rate
Structure
Progressive
Burden @ $100K
$59

54

West Virginia

16.02% top marginal rate
Structure
Progressive
Burden @ $100K
$7,679
Selected

46

South Dakota

16.24% top marginal rate
Structure
Progressive
Burden @ $100K
$5,905

19

Iowa

20.01% top marginal rate
Structure
Progressive
Burden @ $100K
$20,753

78

Virgin Islands

29.17% top marginal rate
Structure
Progressive
Burden @ $100K
$24

Bridges Needing Most Attention in South Dakota

Six lowest-condition bridges in South Dakota, ranked by composite NBI rating. Each is inspected at least every 24 months.

483 AVENUE

Structurally Deficient

Over: WHETSTONE RV

4.8E & 3.2N MILBANK, Grant, SD

Built 1962 Load: 0.9 t ADT: 25

202ND ST.

Structurally Deficient

Over: BEAR BUTTE CK

5.3E BEAR BUTTE, Meade, SD

Built 2000 Load: 0.9 t ADT: 50

45980 303 ST.

Structurally Deficient

Over: VERMILLION RV

6S & 7.8E IRENE, Clay, SD

Built 1909 Load: 1.8 t ADT: 15

460th Avenue

Structurally Deficient

Over: Big Coulee Creek

4S & 2W of Peever, Roberts, SD

Built 1950 Load: 2.2 t ADT: 22

197TH ST

Structurally Deficient

Over: TURTLE CK

1N & 1E ST LAWRENCE, Hand, SD

Built 1925 Load: 2.5 t ADT: 25

242 ST

Structurally Deficient

Over: CK

1.8E 11.0N PLANKINTON, Aurora, SD

Built 1917 Load: 2.7 t ADT: 101

All Bridges in South Dakota

476 AVENUE

Fair

Over: CK

4E & 0.5N STRANDBURG, Grant, SD

Built 1931 Load: 24.5 t ADT: 137

153 STREET

Fair

Over: CK

0.7W & 4S MILBANK, Grant, SD

Built 1974 Load: 24.5 t ADT: 52

W. MILBANK ST-MILB

Fair

Over: SOUTH FORK WHETSTONE RV

0.6W MILBANK, Grant, SD

Built 1984 Load: 24.5 t ADT: 450

MAIN ST-MILBANK

Fair

Over: SOUTH FORK WHETSTONE RV

EASTMAN AVE. MILBANK, Grant, SD

Built 1990 Load: 24.5 t ADT: 200

155 ST

Fair

Over: CK

6.0S & 2.7E MILBANK, Grant, SD

Built 2003 Load: 24.5 t ADT: 75

482 AVENUE

Fair

Over: WHETSTONE RV

4E & 3.2N MILBANK, Grant, SD

Built 1978 Load: 24.5 t ADT: 57

486 AVENUE

Fair

Over: CK

4.5E & 1.8S REVILLO, Grant, SD

Built 1973 Load: 24.5 t ADT: 55

295 STREET

Fair

Over: PONCA CK

4S & 2.5W BURKE, Gregory, SD

Built 1982 Load: 24.5 t ADT: 35

342 AVENUE

Fair

Over: CK

2W & 5.3S BURKE, Gregory, SD

Built 1932 Load: 24.5 t ADT: 36

355 AVENUE

Fair

Over: PONCA CK

6W & 4.1S BONESTEEL, Gregory, SD

Built 1991 Load: 24.5 t ADT: 36

W. WHETSTONE ROAD

Fair

Over: NORTH FORK WHETSTONE CK

1.8W & 9N BONESTEEL, Gregory, SD

Built 1982 Load: 24.5 t ADT: 32

361 AVENUE

Fair

Over: CK

0.5W & 5.5S BONESTEEL, Gregory, SD

Built 1978 Load: 24.5 t ADT: 65

371 AVENUE

Fair

Over: SOUTH SCALP CK

4.2N US 18, Gregory, SD

Built 1977 Load: 24.5 t ADT: 23

371 AVENUE

Fair

Over: SOUTH SCALP CK

5N US HWY 18, Gregory, SD

Built 1977 Load: 24.5 t ADT: 23

Slovak Road

Fair

Over: DEADMANS CK

11N & 11W PHILIP, Haakon, SD

Built 1955 Load: 24.5 t ADT: 28

COUCH ROAD

Fair

Over: GRINDSTONE CK

7 N & 1.8 W PHILIP, Haakon, SD

Built 1930 Load: 24.5 t ADT: 28

Harding Grove Road

Fair

Over: WEST PLUM CK

7.7E&3.5N MILESVILLE, Haakon, SD

Built 1988 Load: 24.5 t ADT: 28

446th Avenue

Fair

Over: Lake Marsh Inlet

4W & 0.2N of Hayti, Hamlin, SD

Built 1936 Load: 24.5 t ADT: 135

188th Street

Fair

Over: Lake Marsh Inlet

3.8W of Hayti, Hamlin, SD

Built 1941 Load: 24.5 t ADT: 261

450th Avenue

Fair

Over: Lake St. John Outlet

2.6S of Lake Norden, Hamlin, SD

Built 1930 Load: 24.5 t ADT: 324

195th St 452nd Ave

Fair

Over: Lake St. John Outlet

2.1E&1.8S of Lake Norden, Hamlin, SD

Built 1992 Load: 24.5 t ADT: 66

459th Avenue

Fair

Over: Lake Poinsett Outlet

6W & 1.7N of Estelline, Hamlin, SD

Built 1974 Load: 24.5 t ADT: 200

190th Street

Fair

Over: Big Sioux River

7S & 2E of Castlewood, Hamlin, SD

Built 1980 Load: 24.5 t ADT: 75

463rd Avenue

Fair

Over: Trib. to Big Sioux River

2.6N of Dempster, Hamlin, SD

Built 1926 Load: 24.5 t ADT: 125

464th Avenue

Fair

Over: Trib. to Stray Horse Crk

5E & 4.8N of Castlewood, Hamlin, SD

Built 1967 Load: 24.5 t ADT: 59

348TH AVE

Fair

Over: WOLF CK

6.1N & 1.2W REE HEIGHTS, Hand, SD

Built 1961 Load: 24.5 t ADT: 67

355 AVE

Fair

Over: CK

0.5 S ORIENT, Hand, SD

Built 1930 Load: 24.5 t ADT: 186

218TH ST

Fair

Over: CROW CK

20S & 4.7W MILLER, Hand, SD

Built 1969 Load: 24.5 t ADT: 15

358TH AVE

Fair

Over: CK

5.4N & 2W MILLER, Hand, SD

Built 1969 Load: 24.5 t ADT: 15

174 ST

Fair

Over: CK

4.9E 2S ORIENT, Hand, SD

Built 1972 Load: 24.5 t ADT: 55

205TH ST

Fair

Over: CK

7S & 0.5E MILLER, Hand, SD

Built 1962 Load: 24.5 t ADT: 73

361 AVE

Fair

Over: CK

6 E & 2.1 S ORIENT, Hand, SD

Built 1925 Load: 24.5 t ADT: 10

361ST AVE

Fair

Over: LITTLE TURTLE CK

5.3N & 1E MILLER, Hand, SD

Built 1962 Load: 24.5 t ADT: 43

362 AVE

Fair

Over: CK

7 E & 1 S ORIENT, Hand, SD

Built 1979 Load: 24.5 t ADT: 15

189 ST

Fair

Over: WOLF CK

4.7 E & 8 N MILLER, Hand, SD

Built 1982 Load: 24.5 t ADT: 43

366 AVE

Fair

Over: CK

6 E & 20.9 N MILLER, Hand, SD

Built 1970 Load: 24.5 t ADT: 76

368 AVE

Fair

Over: NORTH WOLF CK

1.9N 1.1W BURDETTE, Hand, SD

Built 1964 Load: 24.5 t ADT: 25

196TH ST

Fair

Over: PEARL CK

2N & 8.1E MILLER, Hand, SD

Built 1969 Load: 24.5 t ADT: 55

213TH ST

Fair

Over: SAND CK

15S & 9.2E MILLER, Hand, SD

Built 2002 Load: 24.5 t ADT: 25

177 ST

Fair

Over: CK

5S 1.8E ROCKHAM SD, Hand, SD

Built 1966 Load: 24.5 t ADT: 25

370 AVE

Fair

Over: WOLF CK

10E & 12.5N MILLER, Hand, SD

Built 1969 Load: 24.5 t ADT: 43

373 AVE

Fair

Over: CK

4E & 8.2S ROCKHAM, Hand, SD

Built 1969 Load: 24.5 t ADT: 15

372ND AVE

Fair

Over: TURTLE CK

2W & 10.2N WESSINGTON, Hand, SD

Built 1968 Load: 24.5 t ADT: 15

373RD AVE

Fair

Over: CK

1W & 2.5N WESSINGTON, Hand, SD

Built 1978 Load: 24.5 t ADT: 25

373RD AVE

Fair

Over: SAND CK

1W & 8.5S WESSINGTON SPRG, Hand, SD

Built 1969 Load: 24.5 t ADT: 15

374TH AVE

Fair

Over: TURTLE CK

8.6N WESSINGTON, Hand, SD

Built 1966 Load: 24.5 t ADT: 97

374TH AVE

Fair

Over: CK

0.4N WESSINGTON SPRINGS, Hand, SD

Built 1964 Load: 24.5 t ADT: 193

41411 266 STREET

Fair

Over: TWELVE MILE CK

9S & 6.9W ALEXANDRIA, Hanson, SD

Built 1965 Load: 24.5 t ADT: 45

41690 257 AVENUE

Fair

Over: JOHNSON CK

4.1 W ALEXANDRIA, Hanson, SD

Built 1964 Load: 24.5 t ADT: 185

24920 417 AVENUE

Fair

Over: ROCK CK

2 W & 2.8 N FULTON, Hanson, SD

Built 1960 Load: 24.5 t ADT: 60

Showing 1,351-1,400 of 5,905 bridges

Related

All states → | National rankings → | Understanding conditions → | SD bridges explained →
Data sourced from the FHWA National Bridge Inventory (NBI), latest released cycle. See our methodology for details. Retrieved and formatted by PlainBridges Editorial.

Disclaimer: This information is provided for informational purposes only and does not constitute professional advice. Data is sourced from the FHWA National Bridge Inventory (NBI). A "structurally deficient" rating is a repair-priority signal, not a closure or unsafe-to-cross designation. Consult a qualified civil engineer before making decisions based on this data.

Understanding Bridge Conditions

How FHWA rates bridge condition on a 0-9 scale.

Check Your Daily Bridges

How to look up bridge condition data for bridges on your route.

Read our methodology — how this data is sourced, computed, and verified.