County profile · official public datasets

Fall River County, SD

80 public highway bridges tracked in the FHWA National Bridge Inventory: 50% rated Good, 42.5% Fair, 7.5% Poor.

80
Public bridges: 50%
Good condition: 7.5%
Poor condition

The verdict

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

Fall River 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 26%
lowest Poor share in state: 7.5%
Poor-condition share: 80
public highway bridges: 1982
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.

Fall River County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Fall River County ranks #17 of 66 South Dakota counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 7.5%). Fall River County, South Dakota contains 80 public highway bridges. Roughly 50% are rated “Good,” 42.5% “Fair,” and 7.5% “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 Fall River County

Good condition

50%

40 of 80 rated 7-9

Fair condition

42.5%

34 of 80 rated 5-6

Poor condition

7.5%

6 of 80 rated 4 or below

In-state Poor-share rank

#17 of 66

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

Condition distribution

Share of 80 NBI-tracked bridges by lowest applicable component rating.

Good

50% (40)

Fair

42.5% (34)

Poor

7.5% (6)

Fall River County's Poor-condition bridges carry 810 vehicle crossings a day

That is 1.1% of the county's reported daily bridge traffic on 7.5% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 135 crossings a day against 396 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 80 of 80 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

28.8% of Fall River County's bridges have passed the 50-year mark

23 of the 80 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 50% 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 72.6% of the county's Poor-condition bridge traffic

MINNEKAHTA AVENUE over FALL RV, built 1934, carries 588 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 6-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 810 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1930s

6
1940s

2
1950s

10
1960s

4
1970s

11
1980s

13
1990s

11
2000s

8
2010s

12
2020s

3

What this shows Construction peaked in the 1980s, when 13 of the county's bridges still in the inventory were built, which is 16.3% of those with a recorded year. That cohort is now 35 to 44 years old in the 2024 inventory. Its average build year is 1982, 7 years newer than the South Dakota average of 1975.

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

The 5 South Dakota counties nearest Fall River County in number of bridges, with their condition splits. Its 7.5% Poor share is the 2nd-lowest of these 6. Its average build year of 1982 against a peer-group mean of 1973 is 9 years newer.

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

Bridge inventory size and condition shares for Fall River County and the 5 South Dakota counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Jackson County	89	29.2%	55.1%	15.7%	1969
Moody County	87	29.9%	46%	24.1%	1973
Fall River County (this page)	80	50%	42.5%	7.5%	1982
Lake County	79	44.3%	49.4%	6.3%	1977
Codington County	74	20.3%	63.5%	16.2%	1976
Deuel County	72	22.2%	61.1%	16.7%	1971

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

Similar inventory size

Nearest county inventories outside SD (80 bridges here).

Moffat County, CO · 80 bridges
Burke County, GA · 80 bridges
Gooding County, ID · 80 bridges
Madison County, ID · 80 bridges

Similar average build year

Nearest mean year-built outside SD (1982 here).

Oklahoma County, OK · avg 1982 · 1,216 bridges
Jackson County, MO · avg 1982 · 930 bridges
Milwaukee County, WI · avg 1982 · 893 bridges
Champaign County, IL · avg 1982 · 727 bridges

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

All 80 Good 40 Fair 34 Poor 6

Good-condition bridges (40)

Sort:

Fall River County Bridge Snapshot

Condition distribution

Fall River County's Poor-condition bridges carry 810 vehicle crossings a day

28.8% of Fall River County's bridges have passed the 50-year mark

One structure carries 72.6% of the county's Poor-condition bridge traffic

How Fall River 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 (40)

SUNNY BROOK ROAD

DEWEY RD

E. ARDMORE RD

LENNON SCHOOL ROAD

ASH ROAD

SAND CREEK ROAD

SMITHWICK ROAD

GRAVEL ROAD

HIGHLINE ROAD

E. ORAL RD.

ORAL ROAD

US385

W. ARDMORE ROAD

SD071

US385

COUNTY RD

US018 P

US018 W

COUNTY RD 21

OLD HIGHWAY 79

US385

SD471

PINE HILLS ROAD

INDIAN CANYON

SD071

JENNINGS AVENUE

OLD HIGHWAY 18

SD071

US385

SD071

E. ARDMORE ROAD

EDGEMONT RD

SD071

OLD HIGHWAY 18

US385

COUNTY RD

OLD HIGHWAY 79

COUNTY RD

SD471

SD071

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