County profile · official public datasets

Codington County, SD

74 public highway bridges tracked in the FHWA National Bridge Inventory: 20.3% rated Good, 63.5% Fair, 16.2% Poor.

74
Public bridges
20.3%
Good condition
16.2%
Poor condition

The verdict

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

Codington County posts a higher-than-median Poor-condition share among rated counties in the state across rated county bridge inventory.

39th
of 66 on Poor share
16.2%
Poor-condition share
74
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.

Codington County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Codington County ranks #39 of 66 South Dakota counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 16.2%). Codington County, South Dakota contains 74 public highway bridges. Roughly 20.3% are rated “Good,” 63.5% “Fair,” and 16.2% “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

74

Public highway bridges in Codington County

Good condition

20.3%

15 of 74 rated 7-9

Fair condition

63.5%

47 of 74 rated 5-6

Poor condition

16.2%

12 of 74 rated 4 or below

In-state Poor-share rank

#39 of 66

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

Condition distribution

Share of 74 NBI-tracked bridges by lowest applicable component rating.

Good
20.3% (15)
Fair
63.5% (47)
Poor
16.2% (12)

Codington County's Poor-condition bridges carry 9,191 vehicle crossings a day

That is 6.9% of the county's reported daily bridge traffic on 16.2% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 766 crossings a day against 1,818 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 74 of 74 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

55.4% of Codington County's bridges have passed the 50-year mark

41 of the 74 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 20.3% 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 54.1% of the county's Poor-condition bridge traffic

14TH AVE. N WTN. over BIG SIOUX RV, built 1974, carries 4,970 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 12-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 9,191 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Codington County's bridges were built

74 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1970s, when 23 of the county's bridges still in the inventory were built, which is 31.1% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year (1976) matches the South Dakota average (1975).

Source FHWA National Bridge Inventory (year built) As of 2024 NBI release

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

The 5 South Dakota counties nearest Codington County in number of bridges, with their condition splits. Its 16.2% Poor share is the 4th-lowest of these 6. Its average build year of 1976 against a peer-group mean of 1975 is in line with the group.

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

Bridge inventory size and condition shares for Codington County and the 5 South Dakota counties closest to it in inventory size
County Bridges Poor
Fall River County 80 7.5%
Lake County 79 6.3%
Codington County (this page) 74 16.2%
Deuel County 72 16.7%
Haakon County 69 13%
Miner County 64 26.6%

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

Similar inventory size

Nearest county inventories outside SD (74 bridges here).

Similar average build year

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

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

All 74 Good 15 Fair 47 Poor 12

Poor-condition bridges (12)

167 STREET

Poor

Over: WILLOW CK

2.2W 5N KRANZBURG, Codington, SD

Built 1910 Load: 2.7 t ADT: 73

172 STREET

Poor

Over: CK

3.6E 1.0N HENRY, Codington, SD

Built 1940 Load: 5.4 t ADT: 73

COTTONWOOD STREET

Poor

Over: BIG SIOUX RV

12.3W .5N SOUTHSHORE, Codington, SD

Built 1973 Load: 13.6 t ADT: 40

177 STREET

Poor

Over: BIG SIOUX RV

5.0S 2.5E WATERTOWN, Codington, SD

Built 1920 Load: 13.6 t ADT: 73

14TH AVE. N WTN.

Poor

Over: BIG SIOUX RV

2 N 1.2W WATERTOWN, Codington, SD

Built 1974 Load: 18.1 t ADT: 4,970

455 AVENUE

Poor

Over: MAHONEY CK

3.3 S JCT SD 20 E, Codington, SD

Built 1940 Load: 18.1 t ADT: 1,167

455 AVENUE

Poor

Over: CK

0.9 N JCT SD 20 W, Codington, SD

Built 1940 Load: 19.1 t ADT: 672

162 STREET

Poor

Over: BIG SIOUX RV

7.5E & 1S FLORENCE, Codington, SD

Built 1985 Load: 20.0 t ADT: 40

OAK STREET

Poor

Over: WILLOW CK

5.2E 3.5N WATERTOWN, Codington, SD

Built 1988 Load: 21.8 t ADT: 60

SIOUX CONIFER ROAD

Poor

Over: BIG SIOUX RV

3.6N 2.0W WATERTOWN, Codington, SD

Built 1940 Load: 24.5 t ADT: 1,499

SD020 P

Poor

Over: CK

NORTH LAKE KAMPESKA, Codington, SD

Built 1931 Load: 25.1 t ADT: 56

176 STREET

Poor

Over: BIG SIOUX RV

4.0S 2.6E WATERTOWN, Codington, SD

Built 1971 Load: 26.3 t ADT: 468

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

Related

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Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainBridges

Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.