County profile · official public datasets

Ionia County, MI

119 public highway bridges tracked in the FHWA National Bridge Inventory: 32.8% rated Good, 58.8% Fair, 8.4% Poor.

119
Public bridges
32.8%
Good condition
8.4%
Poor condition

The verdict

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

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

Top 41%
lowest Poor share in state
8.4%
Poor-condition share
119
public highway bridges
1974
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.

Ionia County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Ionia County ranks #34 of 83 Michigan counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 8.4%). Ionia County, Michigan contains 119 public highway bridges. Roughly 32.8% are rated “Good,” 58.8% “Fair,” and 8.4% “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

119

Public highway bridges in Ionia County

Good condition

32.8%

39 of 119 rated 7-9

Fair condition

58.8%

70 of 119 rated 5-6

Poor condition

8.4%

10 of 119 rated 4 or below

In-state Poor-share rank

#34 of 83

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

Condition distribution

Share of 119 NBI-tracked bridges by lowest applicable component rating.

Good
32.8% (39)
Fair
58.8% (70)
Poor
8.4% (10)

Ionia County's Poor-condition bridges carry 7,750 vehicle crossings a day

That is 1.6% of the county's reported daily bridge traffic on 8.4% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 775 crossings a day against 2,513 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 119 of 119 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

47.1% of Ionia County's bridges have passed the 50-year mark

56 of the 119 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 32.8% 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 32.7% of the county's Poor-condition bridge traffic

M-21 over MAPLE RIVER, built 1929, carries 2,533 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 10-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 7,750 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Ionia County's bridges were built

119 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1950s, when 26 of the county's bridges still in the inventory were built, which is 21.8% of those with a recorded year. That cohort is now 65 to 74 years old in the 2024 inventory. Its average build year (1974) matches the Michigan average (1976).

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

How Ionia County compares with Michigan's closest counties by inventory size

The 5 Michigan counties nearest Ionia County in number of bridges, with their condition splits. Its 8.4% Poor share is the 3rd-lowest of these 6. Its average build year of 1974 against a peer-group mean of 1976 is in line with the group.

Showing the 5 closest of 82 Michigan counties eligible for comparison.

Bridge inventory size and condition shares for Ionia County and the 5 Michigan counties closest to it in inventory size
County Bridges Poor
St. Joseph County 132 12.1%
Van Buren County 129 7%
Montcalm County 121 5%
Ionia County (this page) 119 8.4%
Branch County 118 21.2%
Chippewa County 112 12.5%

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

Similar inventory size

Nearest county inventories outside MI (119 bridges here).

Similar average build year

Nearest mean year-built outside MI (1974 here).

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

All 119 Good 39 Fair 70 Poor 10

All bridges (119)

DUMON ROAD

Good

Over: MILLE RACE

0.5 MILES EAST OF SYMRNA, Ionia, MI

Built 1999 Load: 57.7 t ADT: 102

RIVERSIDE DRIVE

Good

Over: LIBHART CREEK

0.7 MI W VILL LMTS LYONS, Ionia, MI

Built 2014 Load: 58.3 t ADT: 1,393

CLEVELAND STREET

Good

Over: GRAND RIVER

1.2MI E M66 @ S LMT IONIA, Ionia, MI

Built 2013 Load: 60.6 t ADT: 4,512

HASTINGS ROAD

Good

Over: TYLER CREEK

2.25 MI W OF CLARKSVILLE, Ionia, MI

Built 2008 Load: 63.5 t ADT: 1,183

KEEFER HWY

Good

Over: SEBEWA CREEK

2 MI W PORTLAND 5.6 MI S., Ionia, MI

Built 2014 Load: 65.8 t ADT: 971

LYLE ROAD

Good

Over: BELLAMY CREEK

0.5 MI N 1.5 MI W OFIONIA, Ionia, MI

Built 2005 Load: 67.4 t ADT: 107

ASHFIELD ST

Good

Over: FLAT RIVER

IN BELDING, Ionia, MI

Built 1994 Load: 70.1 t ADT: 1,733

KENT STREET

Good

Over: GRAND RIVER

KENT ST S PORTLD VILL LMT, Ionia, MI

Built 2002 Load: 81.6 t ADT: 1,222

I-96

Good

Over: PORTLAND TRAIL

1.0 M SE OF PORTLAND, Ionia, MI

Built 2013 Load: 89.7 t ADT: 35,000

BELL ROAD

Poor

Over: DUCK CREEK

1.25 MI W 3.5 MI S CLARKS, Ionia, MI

Built 1970 Load: 3.6 t ADT: 40

REEDER ROAD

Poor

Over: LIBHART CREEK

2.0 MILES SOUTH OF LYONS, Ionia, MI

Built 1975 Load: 5.1 t ADT: 152

JACKSON ROAD

Poor

Over: UNNAMED CREEK

1.0 MILE SE OF SARANAC, Ionia, MI

Built 1993 Load: 11.3 t ADT: 321

PECK LAKE ROAD

Poor

Over: LIBHART CREEK

4.0 MI S 0.5 MI E IONIA, Ionia, MI

Built 1982 Load: 13.9 t ADT: 128

BORDEN RD

Poor

Over: PRAIRIE CREEK

1.5 MI S OF PALO & 1.2 E, Ionia, MI

Built 1927 Load: 15.9 t ADT: 462

DIVINE HIGHWAY

Poor

Over: LOOKINGGLASS RIVER

0.05 MI N OF OLD US16 POR, Ionia, MI

Built 1979 Load: 20.9 t ADT: 2,494

GRAND RIVER AVENUE

Poor

Over: LIBHART CREEK

5 MI S OF IONIA & 1 MI E, Ionia, MI

Built 1936 Load: 24.0 t ADT: 1,093

HUDDLE ROAD

Poor

Over: TUPPER CREEK

0.25 MI E OF LAKE ODESSA, Ionia, MI

Built 1923 Load: 32.7 t ADT: 123

NICKLE PLATE RD

Poor

Over: MAPLE RIVER FLOOD

2 MI N PEWAMO & 2 MI WEST, Ionia, MI

Built 1983 Load: 33.0 t ADT: 404

M-21

Poor

Over: MAPLE RIVER

1.0 MI E OF MUIR, Ionia, MI

Built 1929 Load: 35.6 t ADT: 2,533

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.