Total bridges
119
Public highway bridges in Ionia County
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.
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
- pre-1900 2
Built before 1900
2 bridges
- 1920s 10
1920–1929
10 bridges
- 1930s 5
1930–1939
5 bridges
- 1940s 2
1940–1949
2 bridges
- 1950s
1950–1959
26 bridges
- 1960s 4
1960–1969
4 bridges
- 1970s
1970–1979
13 bridges
- 1980s
1980–1989
19 bridges
- 1990s
1990–1999
12 bridges
- 2000s
2000–2009
12 bridges
- 2010s
2010–2019
12 bridges
- 2020s 2
2020–2029
2 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).
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.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| St. Joseph County | 132 | 28.8% | 59.1% | 12.1% | 1979 |
| Van Buren County | 129 | 32.6% | 60.5% | 7% | 1976 |
| Montcalm County | 121 | 37.2% | 57.9% | 5% | 1977 |
| Ionia County (this page) | 119 | 32.8% | 58.8% | 8.4% | 1974 |
| Branch County | 118 | 24.6% | 54.2% | 21.2% | 1973 |
| Chippewa County | 112 | 22.3% | 65.2% | 12.5% | 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 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).
- Carroll County, AR · 119 bridges
- Grant County, AR · 119 bridges
- Stafford County, KS · 119 bridges
- Grayson County, KY · 119 bridges
Similar average build year
Nearest mean year-built outside MI (1974 here).
- Knox County, TN · avg 1974 · 588 bridges
- Summit County, OH · avg 1974 · 563 bridges
- Onondaga County, NY · avg 1974 · 472 bridges
- Orange County, NY · avg 1974 · 472 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
Poor-condition bridges (10)
BELL ROAD
PoorOver: DUCK CREEK
1.25 MI W 3.5 MI S CLARKS, Ionia, MI
Built 1970 Load: 3.6 t ADT: 40
REEDER ROAD
PoorOver: LIBHART CREEK
2.0 MILES SOUTH OF LYONS, Ionia, MI
Built 1975 Load: 5.1 t ADT: 152
JACKSON ROAD
PoorOver: UNNAMED CREEK
1.0 MILE SE OF SARANAC, Ionia, MI
Built 1993 Load: 11.3 t ADT: 321
PECK LAKE ROAD
PoorOver: LIBHART CREEK
4.0 MI S 0.5 MI E IONIA, Ionia, MI
Built 1982 Load: 13.9 t ADT: 128
BORDEN RD
PoorOver: PRAIRIE CREEK
1.5 MI S OF PALO & 1.2 E, Ionia, MI
Built 1927 Load: 15.9 t ADT: 462
DIVINE HIGHWAY
PoorOver: LOOKINGGLASS RIVER
0.05 MI N OF OLD US16 POR, Ionia, MI
Built 1979 Load: 20.9 t ADT: 2,494
GRAND RIVER AVENUE
PoorOver: LIBHART CREEK
5 MI S OF IONIA & 1 MI E, Ionia, MI
Built 1936 Load: 24.0 t ADT: 1,093
HUDDLE ROAD
PoorOver: TUPPER CREEK
0.25 MI E OF LAKE ODESSA, Ionia, MI
Built 1923 Load: 32.7 t ADT: 123
NICKLE PLATE RD
PoorOver: MAPLE RIVER FLOOD
2 MI N PEWAMO & 2 MI WEST, Ionia, MI
Built 1983 Load: 33.0 t ADT: 404
M-21
PoorOver: 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
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.