County profile · official public datasets

Butte County, SD

143 public highway bridges tracked in the FHWA National Bridge Inventory: 30.8% rated Good, 57.3% Fair, 11.9% Poor.

143
Public bridges: 30.8%
Good condition: 11.9%
Poor condition

The verdict

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

Butte County posts a better-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.

Top 39%
lowest Poor share in state: 11.9%
Poor-condition share: 143
public highway bridges: 1976
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.

Butte County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Butte County ranks #26 of 66 South Dakota counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 11.9%). Butte County, South Dakota contains 143 public highway bridges. Roughly 30.8% are rated “Good,” 57.3% “Fair,” and 11.9% “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

143

Public highway bridges in Butte County

Good condition

30.8%

44 of 143 rated 7-9

Fair condition

57.3%

82 of 143 rated 5-6

Poor condition

11.9%

17 of 143 rated 4 or below

In-state Poor-share rank

#26 of 66

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

Condition distribution

Share of 143 NBI-tracked bridges by lowest applicable component rating.

Good

30.8% (44)

Fair

57.3% (82)

Poor

11.9% (17)

Butte County's Poor-condition bridges carry 816 vehicle crossings a day

That is 1% of the county's reported daily bridge traffic on 11.9% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 48 crossings a day against 312 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 143 of 143 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

49.7% of Butte County's bridges have passed the 50-year mark

71 of the 143 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 30.8% 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 33% of the county's Poor-condition bridge traffic

ARPAN RD over SOUTH CANAL, built 1975, carries 269 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 17-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 816 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1900s

2
1910s

1
1920s

2
1930s

10
1940s

7
1950s

16
1960s

30
1970s

10
1980s

10
1990s

26
2000s

11
2010s

8
2020s

10

What this shows Construction peaked in the 1960s, when 30 of the county's bridges still in the inventory were built, which is 21% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year (1976) matches the South Dakota average (1975).

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

The 5 South Dakota counties nearest Butte County in number of bridges, with their condition splits. Its 11.9% Poor share is the 1st-lowest of these 6. Its average build year of 1976 against a peer-group mean of 1970 is 6 years newer.

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

Bridge inventory size and condition shares for Butte County and the 5 South Dakota counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Roberts County	157	22.9%	52.9%	24.2%	1970
Beadle County	152	19.1%	47.4%	33.6%	1955
Turner County	143	38.5%	35.7%	25.9%	1984
Butte County (this page)	143	30.8%	57.3%	11.9%	1976
Lawrence County	136	36%	51.5%	12.5%	1980
Bon Homme County	126	21.4%	50.8%	27.8%	1961

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

Similar inventory size

Nearest county inventories outside SD (143 bridges here).

Franklin County, AR · 143 bridges
San Francisco County, CA · 143 bridges
Woodson County, KS · 143 bridges
Adair County, KY · 143 bridges

Similar average build year

Nearest mean year-built outside SD (1976 here).

Marion County, IN · avg 1976 · 958 bridges
Mohave County, AZ · avg 1976 · 641 bridges
Comanche County, OK · avg 1976 · 593 bridges
Prince George's County, MD · avg 1976 · 576 bridges

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

All 143 Good 44 Fair 82 Poor 17

All bridges (143)

Sort:

Butte County Bridge Snapshot

Condition distribution

Butte County's Poor-condition bridges carry 816 vehicle crossings a day

49.7% of Butte County's bridges have passed the 50-year mark

One structure carries 33% of the county's Poor-condition bridge traffic

How Butte 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 (143)

US212

US212

US085

US085

US085

US085

US212

US085

US085

OLSON CUTOFF ROAD

SD079

SD079

US085

US085

SD079

SD034

SNOMA ROAD

SD079

Inlet Canal Road

ARPAN RD

SD034

SD079

10th Avenue

WHITEWOOD VALLEYRD

VALE CUTOFF RD

US212

SD079

US085

US212

SD079

SD079

SD034

8TH AVENUE

SD079

OWL BASIN RD

REID RD

OLD HWY 85

TAYLOR ROAD

BEET ROAD

BEET RD

OLD HWY 85

MAIL RD

MAIL RD

MAIL RD

VALLERY RD

RILEY RD

WINKLER RD

STONE LAKE RD

SNOMA RD

VALE CUTOFF RD

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