County profile · official public datasets

Linn County, KS

257 public highway bridges tracked in the FHWA National Bridge Inventory: 59.9% rated Good, 35.4% Fair, 4.7% Poor.

257
Public bridges: 59.9%
Good condition: 4.7%
Poor condition

The verdict

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

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

57th
of 104 on Poor share: 4.7%
Poor-condition share: 257
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.

Linn County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Linn County ranks #57 of 104 Kansas counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 4.7%). Linn County, Kansas contains 257 public highway bridges. Roughly 59.9% are rated “Good,” 35.4% “Fair,” and 4.7% “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

257

Public highway bridges in Linn County

Good condition

59.9%

154 of 257 rated 7-9

Fair condition

35.4%

91 of 257 rated 5-6

Poor condition

4.7%

12 of 257 rated 4 or below

In-state Poor-share rank

#57 of 104

Among Kansas counties with 5+ bridges, lower share ranks better

Condition distribution

Share of 257 NBI-tracked bridges by lowest applicable component rating.

Good

59.9% (154)

Fair

35.4% (91)

Poor

4.7% (12)

Linn County's Poor-condition bridges carry 469 vehicle crossings a day

That is 0.4% of the county's reported daily bridge traffic on 4.7% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 39 crossings a day against 691 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 257 of 257 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

38.9% of Linn County's bridges have passed the 50-year mark

100 of the 257 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 59.9% 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 35% of the county's Poor-condition bridge traffic

RS 1204 26 over LITTLE SUGAR CREEK, built 1966, carries 164 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 469 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1910s

6
1920s

5
1930s

21
1950s

21
1960s

31
1970s

45
1980s

61
1990s

25
2000s

33
2010s

8
2020s

1

What this shows Construction peaked in the 1980s, when 61 of the county's bridges still in the inventory were built, which is 23.7% of those with a recorded year. That cohort is now 35 to 44 years old in the 2024 inventory. Its average build year (1976) matches the Kansas average (1972).

How Linn County compares with Kansas's closest counties by inventory size

The 5 Kansas counties nearest Linn County in number of bridges, with their condition splits. Its 4.7% Poor share is the 6th-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 103 Kansas counties eligible for comparison.

Bridge inventory size and condition shares for Linn County and the 5 Kansas counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Rice County	262	48.9%	48.1%	3.1%	1977
Russell County	261	43.7%	54.4%	1.9%	1966
Mitchell County	260	59.6%	36.9%	3.5%	1962
Ellsworth County	259	48.6%	48.6%	2.7%	1970
Linn County (this page)	257	59.9%	35.4%	4.7%	1976
Brown County	256	48.4%	47.7%	3.9%	1974

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 Linn 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 Linn County, both outside Kansas so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside KS (257 bridges here).

District of Columbia County, DC · 257 bridges
Clark County, IN · 257 bridges
Randolph County, IN · 257 bridges
Walsh County, ND · 257 bridges

Similar average build year

Nearest mean year-built outside KS (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 257 Good 154 Fair 91 Poor 12

Good-condition bridges (154)

Sort:

Linn County Bridge Snapshot

Condition distribution

Linn County's Poor-condition bridges carry 469 vehicle crossings a day

38.9% of Linn County's bridges have passed the 50-year mark

One structure carries 35% of the county's Poor-condition bridge traffic

How Linn County compares with Kansas'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 (154)

RS 403 48

US-69 HWY NB & SB

RS 408 18

LOCAL RD. 36

RS 399 37

RS 399 39

RS 399 38

RS 407 14

LOCAL RD. 67

MINOR COL 62D

MINOR COL 57

LOCAL RD. 38

RS 406 10

LOCAL RD 25B

LOCAL RD. 13A

MINOR COL 34A

LOCAL RD. 25AA

LOCAL RD. 25A

LOCAL RD. 45

Local Road 35AB

LOCAL RD. 9

K31 K52 HWY

LOCAL RD. 27

LOCAL RD. 4A

Local Road 67AA

K31 K52 HWY

K52 HWY

K152 HWY

LOCAL RD. 5B

MINOR COL 45AA

LOCAL RD. 58AAA

LOCAL RD. 68

LOCAL RD. 10A

LOCAL RD. 35A

LOCAL RD. 68A

LOCAL RD. 47A

LOCAL RD. 47AA

LOCAL RD. 58AA

LOCAL RD. 14A1

LOCAL RD. 58A1

LOCAL RD. 64A

LOCAL RD. 62A

LOCAL RD. 62C

LOCAL RD. 18A1

LOCAL RD. 18A2

LOCAL RD. 5C

LOCAL RD. 10D

LOCAL RD. 18B

LOCAL RD. 7

LOCAL RD. 50B

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