County profile · official public datasets

Hardin County, IA

241 public highway bridges tracked in the FHWA National Bridge Inventory: 36.1% rated Good, 36.1% Fair, 27.8% Poor.

241
Public bridges
36.1%
Good condition
27.8%
Poor condition

The verdict

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

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

74th
of 99 on Poor share
27.8%
Poor-condition share
241
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.

Hardin County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Hardin County ranks #74 of 99 Iowa counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 27.8%). Hardin County, Iowa contains 241 public highway bridges. Roughly 36.1% are rated “Good,” 36.1% “Fair,” and 27.8% “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

241

Public highway bridges in Hardin County

Good condition

36.1%

87 of 241 rated 7-9

Fair condition

36.1%

87 of 241 rated 5-6

Poor condition

27.8%

67 of 241 rated 4 or below

In-state Poor-share rank

#74 of 99

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

Condition distribution

Share of 241 NBI-tracked bridges by lowest applicable component rating.

Good
36.1% (87)
Fair
36.1% (87)
Poor
27.8% (67)

Hardin County's Poor-condition bridges carry 12,044 vehicle crossings a day

That is 6.4% of the county's reported daily bridge traffic on 27.8% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 180 crossings a day against 1,582 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 241 of 241 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

26.1% of Hardin County's bridges have passed the 50-year mark

63 of the 241 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 36.1% 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 15.4% of the county's Poor-condition bridge traffic

MAIN ST over IOWA RIVER, built 1936, carries 1,858 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 67-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 12,044 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Hardin County's bridges were built

241 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1980s, when 59 of the county's bridges still in the inventory were built, which is 24.5% of those with a recorded year. That cohort is now 35 to 44 years old in the 2024 inventory. Its average build year (1981) matches the Iowa average (1979).

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

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

The 5 Iowa counties nearest Hardin County in number of bridges, with their condition splits. Its 27.8% Poor share is the 4th-lowest of these 6. Its average build year of 1981 against a peer-group mean of 1978 is in line with the group.

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

Bridge inventory size and condition shares for Hardin County and the 5 Iowa counties closest to it in inventory size
County Bridges Poor
Cherokee County 248 29%
Poweshiek County 248 41.9%
Jackson County 246 17.1%
Iowa County 241 19.1%
Hardin County (this page) 241 27.8%
Warren County 239 20.5%

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

Similar inventory size

Nearest county inventories outside IA (241 bridges here).

Similar average build year

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

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

All 241 Good 87 Fair 87 Poor 67

Good-condition bridges (87)

260TH ST

Good

Over: BEAR CREEK

087192601, Hardin, IA

Built 2017 Load: 38.9 t ADT: 21

D AVENUE

Good

Over: US 20

2.0 MILES W OF SR S27, Hardin, IA

Built 1990 Load: 39.1 t ADT: 44

LOCAL

Good

Over: SMALL STREAM

086210904, Hardin, IA

Built 1994 Load: 39.7 t ADT: 30

US 65

Good

Over: BEAVER CREEK

1.6 MILES N OF JCT SR D25, Hardin, IA

Built 1976 Load: 39.9 t ADT: 5,300

SDB

Good

Over: DOWD CREEK

086193601, Hardin, IA

Built 2009 Load: 39.9 t ADT: 766

D55 290TH ST

Good

Over: DRAINAGE

086191101, Hardin, IA

Built 2016 Load: 40.2 t ADT: 69

US 20 EB

Good

Over: US 65

AT JUNCTION WITH US 65, Hardin, IA

Built 2003 Load: 40.2 t ADT: 4,100

US 20 WB

Good

Over: US 65

AT JUNCTION WITH US 65, Hardin, IA

Built 2003 Load: 40.2 t ADT: 4,100

S 56

Good

Over: US 20

AT JUNCTION WITH SR S56, Hardin, IA

Built 2003 Load: 40.5 t ADT: 1,453

US 20

Good

Over: DRAINAGE

0.3 MILE E OF JCT SR S56, Hardin, IA

Built 2003 Load: 40.5 t ADT: 9,200

US 20 WB

Good

Over: D 35 (ELM ST)

3.4 MILES E OF JCT US 65, Hardin, IA

Built 2003 Load: 41.0 t ADT: 4,900

S57

Good

Over: HONEY CREEK

086201502, Hardin, IA

Built 2022 Load: 41.5 t ADT: 344

RR AVE

Good

Over: HONEY CREEK

086202303, Hardin, IA

Built 2011 Load: 41.5 t ADT: 29

260TH ST

Good

Over: BEAVER CREEK

087202501, Hardin, IA

Built 2019 Load: 41.5 t ADT: 91

M AVE

Good

Over: SOUTH FORK OF IOWA RIVER

087210102, Hardin, IA

Built 2021 Load: 41.5 t ADT: 47

LOCAL

Good

Over: TIPTON CREEK

087210701, Hardin, IA

Built 1991 Load: 41.7 t ADT: 11

EB US 20

Good

Over: SOUTH FORK IOWA RIVER

1.0 MILE E OF JCT SR S27, Hardin, IA

Built 1999 Load: 42.8 t ADT: 4,650

X AVE

Good

Over: PINE CREEK

087190304, Hardin, IA

Built 2021 Load: 43.1 t ADT: 51

US 20 EB

Good

Over: BEAVER CREEK

4.4 MILES E OF JCT. US 65, Hardin, IA

Built 2003 Load: 43.3 t ADT: 4,850

US 20 WB

Good

Over: BEAVER CREEK

4.4 MILES EAST JCT US 65, Hardin, IA

Built 2003 Load: 43.3 t ADT: 4,850

T AVENUE

Good

Over: US 20

1.2 MILES E OF JCT SR D35, Hardin, IA

Built 2003 Load: 43.6 t ADT: 108

IA 175

Good

Over: SO FORK IOWA RIVER

2.5 mi. E of E Jct. US 65, Hardin, IA

Built 1981 Load: 44.1 t ADT: 1,740

US 20 EB

Good

Over: UPRR

1.5 MILES E OF JCT SR S27, Hardin, IA

Built 1999 Load: 44.4 t ADT: 4,650

US 65

Good

Over: S. FORK IOWA RIVER

0.6 MI N OF N JCT IA 175, Hardin, IA

Built 2007 Load: 46.2 t ADT: 1,970

D35

Good

Over: US 20

AT JUNCTION SR D35, Hardin, IA

Built 2003 Load: 46.2 t ADT: 717

US 65

Good

Over: HONEY CREEK

AT JCT SR D55/280TH ST, Hardin, IA

Built 2008 Load: 47.1 t ADT: 1,820

M AVE

Good

Over: HONEY CREEK

086211202, Hardin, IA

Built 2000 Load: 48.2 t ADT: 62

LOCAL

Good

Over: TIPTON CREEK

087212603, Hardin, IA

Built 2003 Load: 50.0 t ADT: 30

US 65

Good

Over: MINERVA CREEK

0.7 MILES S OF JCT SR D65, Hardin, IA

Built 1985 Load: 50.2 t ADT: 1,330

LOCAL

Good

Over: CREEK

086213402, Hardin, IA

Built 2006 Load: 52.9 t ADT: 25

LOCAL

Good

Over: BEAVER CREEK

087201303, Hardin, IA

Built 2003 Load: 52.9 t ADT: 51

L AVE

Good

Over: TIPTON CREEK

087212206, Hardin, IA

Built 2007 Load: 52.9 t ADT: 5

FM

Good

Over: IA RIVER

088212704, Hardin, IA

Built 2001 Load: 52.9 t ADT: 34

FM

Good

Over: DRAINAGE DITCH

088220601, Hardin, IA

Built 2005 Load: 52.9 t ADT: 177

LOCAL

Good

Over: IOWA RIVER

088221303, Hardin, IA

Built 1995 Load: 52.9 t ADT: 39

FM

Good

Over: MINERVA CREEK

086220902, Hardin, IA

Built 1998 Load: 58.8 t ADT: 236

IA 175

Good

Over: ROBERTS CREEK

0.6 MILE WEST OF SR D41, Hardin, IA

Built 1972 Load: 90.5 t ADT: 1,670

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

Related

Browse all → | Rankings →
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.