County profile · official public datasets

Hancock County, IA

138 public highway bridges tracked in the FHWA National Bridge Inventory: 39.9% rated Good, 39.9% Fair, 20.3% Poor.

138
Public bridges: 39.9%
Good condition: 20.3%
Poor condition

The verdict

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

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

55th
of 99 on Poor share: 20.3%
Poor-condition share: 138
public highway bridges: 1981
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.

Hancock County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Hancock County ranks #55 of 99 Iowa counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 20.3%). Hancock County, Iowa contains 138 public highway bridges. Roughly 39.9% are rated “Good,” 39.9% “Fair,” and 20.3% “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

138

Public highway bridges in Hancock County

Good condition

39.9%

55 of 138 rated 7-9

Fair condition

39.9%

55 of 138 rated 5-6

Poor condition

20.3%

28 of 138 rated 4 or below

In-state Poor-share rank

#55 of 99

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

Condition distribution

Share of 138 NBI-tracked bridges by lowest applicable component rating.

Good

39.9% (55)

Fair

39.9% (55)

Poor

20.3% (28)

Hancock County's Poor-condition bridges carry 5,483 vehicle crossings a day

That is 9.6% of the county's reported daily bridge traffic on 20.3% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 196 crossings a day against 262 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 138 of 138 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

37.7% of Hancock County's bridges have passed the 50-year mark

52 of the 138 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 39.9% 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 40% of the county's Poor-condition bridge traffic

FM 1870 330TH over WINNEBAGO RIVER, built 1963, carries 2,192 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 28-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 5,483 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1920s

4
1930s

3
1940s

2
1950s

19
1960s

15
1970s

29
1980s

20
1990s

7
2000s

17
2010s

17
2020s

5

What this shows Construction peaked in the 1970s, when 29 of the county's bridges still in the inventory were built, which is 21% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year (1981) matches the Iowa average (1979).

How Hancock County compares with Iowa's closest counties by inventory size

The 5 Iowa counties nearest Hancock County in number of bridges, with their condition splits. Its 20.3% Poor share is the 3rd-lowest of these 6. Its average build year of 1981 against a peer-group mean of 1973 is 8 years newer.

Showing the 5 closest of 98 Iowa counties eligible for comparison.

Bridge inventory size and condition shares for Hancock County and the 5 Iowa counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Clay County	151	35.8%	54.3%	9.9%	1982
Muscatine County	144	34.7%	43.8%	21.5%	1979
Hancock County (this page)	138	39.9%	39.9%	20.3%	1981
Boone County	135	27.4%	43%	29.6%	1955
Palo Alto County	135	23%	58.5%	18.5%	1973
Monroe County	130	26.2%	49.2%	24.6%	1977

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

Similar inventory size

Nearest county inventories outside IA (138 bridges here).

Santa Cruz County, AZ · 138 bridges
Boone County, KY · 138 bridges
Ralls County, MO · 138 bridges
Scurry County, TX · 138 bridges

Similar average build year

Nearest mean year-built outside IA (1981 here).

Franklin County, OH · avg 1981 · 922 bridges
Greenville County, SC · avg 1981 · 635 bridges
Montgomery County, OH · avg 1981 · 632 bridges
McLean County, IL · avg 1981 · 624 bridges

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

All 138 Good 55 Fair 55 Poor 28

Good-condition bridges (55)

Sort:

Hancock County Bridge Snapshot

Condition distribution

Hancock County's Poor-condition bridges carry 5,483 vehicle crossings a day

37.7% of Hancock County's bridges have passed the 50-year mark

One structure carries 40% of the county's Poor-condition bridge traffic

How Hancock County compares with Iowa'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 (55)

1370 UNION AVE

1240 UNION AVE

1390 120TH ST

2460 SIOUX AVE

760 140TH ST

LOCAL

1430 IOWA AVE

610 220TH ST

IA 17

FM 1980 110TH

LOC 2100 UNION

US 69

B55 160TH ST

110TH ST

200TH ST

250TH ST

R16 BIRCH AVE

FM 2160 SIOUX

FM 2080 SIOUX

FM 1930 YALE

LOC 2340 200TH

LOC 2240 200TH

LOC 2280 200TH

190TH ST

LOC 1620 TAFT

B36 (225TH ST)

1270 200TH ST

3220 REED AVE

190 150TH ST

150TH ST

CRANE AVE

170TH ST

225TH ST

B62

1020 QUAIL AVE

FM 220 290TH ST

140TH ST

130TH ST

620 110TH ST

LOC 1220 270 ST

150TH ST

1030 GRANT AVE

950 110TH ST

B-63

110TH ST

1110 220TH ST

LOC 910 250 ST

1995 150TH ST

1340 180TH ST

US 18

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