Total bridges
54
Public highway bridges in Iron County
County profile · official public datasets
Iron County, MI
54 public highway bridges tracked in the FHWA National Bridge Inventory: 20.4% rated Good, 59.3% Fair, 20.4% Poor.
- 54
- Public bridges
- 20.4%
- Good condition
- 20.4%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Iron County pairs a higher-than-median Poor-condition share among rated counties in the state with an older average build year than the state inventory.
- 80th
- of 83 on Poor share
- 20.4%
- Poor-condition share
- 54
- public highway bridges
- 1967
- 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.
Iron County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Iron County ranks #80 of 83 Michigan counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 20.4%). Iron County, Michigan contains 54 public highway bridges. Roughly 20.4% are rated “Good,” 59.3% “Fair,” and 20.4% “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
20.4%
11 of 54 rated 7-9
Fair condition
59.3%
32 of 54 rated 5-6
Poor condition
20.4%
11 of 54 rated 4 or below
In-state Poor-share rank
#80 of 83
Among Michigan counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 54 NBI-tracked bridges by lowest applicable component rating.
Good 20.4% (11)
Fair 59.3% (32)
Poor 20.4% (11)
Iron County's Poor-condition bridges carry 14,413 vehicle crossings a day
That is 27.5% of the county's reported daily bridge traffic on 20.4% of its bridges: Poor-condition structures carry more traffic than their share of the inventory. Each Poor bridge averages 1,310 crossings a day against 304 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 54 of 54 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
53.7% of Iron County's bridges have passed the 50-year mark
29 of the 54 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 20.4% 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 56.9% of the county's Poor-condition bridge traffic
W GENESEE(OLD US2) over IRON RIVER BURIED, built 1918, carries 8,200 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 11-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 14,413 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Iron County's bridges were built
54 bridges with a recorded construction year, grouped by decade
- 1900s 1
1900–1909
1 bridges
- 1910s 2
1910–1919
2 bridges
- 1920s
1920–1929
7 bridges
- 1930s
1930–1939
4 bridges
- 1940s 2
1940–1949
2 bridges
- 1950s
1950–1959
9 bridges
- 1960s 2
1960–1969
2 bridges
- 1970s 2
1970–1979
2 bridges
- 1980s
1980–1989
7 bridges
- 1990s
1990–1999
9 bridges
- 2000s
2000–2009
6 bridges
- 2010s 1
2010–2019
1 bridges
- 2020s 2
2020–2029
2 bridges
What this shows Construction peaked in the 1950s, when 9 of the county's bridges still in the inventory were built, which is 16.7% of those with a recorded year. That cohort is now 65 to 74 years old in the 2024 inventory. Its average build year is 1967, 9 years older than the Michigan average of 1976.
How Iron County compares with Michigan's closest counties by inventory size
The 5 Michigan counties nearest Iron County in number of bridges, with their condition splits. Its 20.4% Poor share is the 6th-lowest of these 6. Its average build year of 1967 against a peer-group mean of 1970 is in line with the group.
Showing the 5 closest of 82 Michigan counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Houghton County | 58 | 63.8% | 32.8% | 3.4% | 1984 |
| Crawford County | 54 | 14.8% | 66.7% | 18.5% | 1971 |
| Schoolcraft County | 54 | 27.8% | 66.7% | 5.6% | 1967 |
| Iron County (this page) | 54 | 20.4% | 59.3% | 20.4% | 1967 |
| Alger County | 53 | 30.2% | 58.5% | 11.3% | 1956 |
| Cass County | 52 | 25% | 59.6% | 15.4% | 1970 |
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 Iron 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 Iron County, both outside Michigan so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside MI (54 bridges here).
- Rio Blanco County, CO · 54 bridges
- Brantley County, GA · 54 bridges
- Jones County, GA · 54 bridges
- Larue County, KY · 54 bridges
Similar average build year
Nearest mean year-built outside MI (1967 here).
- Los Angeles County, CA · avg 1967 · 3,547 bridges
- Allegheny County, PA · avg 1967 · 1,294 bridges
- Sonoma County, CA · avg 1967 · 609 bridges
- Merced County, CA · avg 1967 · 528 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
Fair-condition bridges (32)
FR 146
FairOver: NO BRANCH PAINT RIVER
NE QTR SEC 11 T45N R36W, Iron, MI
Built 1952 Load: 9.1 t ADT: 17
PENTOGA ROAD
FairOver: BRULE RIVER
2.5 MI S OF RD424 PENTOGA, Iron, MI
Built 1924 Load: 12.6 t ADT: 3
FR 146 WINSL
FairOver: WINSLOW CREEK
NE COR SEC 2 T45 R36, Iron, MI
Built 1954 Load: 13.7 t ADT: 17
FOREST ROAD 3470
FairOver: SOUTH BRANCH PAINT RIVER
3.3 MI N OF BEECHWOOD, Iron, MI
Built 1952 Load: 15.9 t ADT: 50
FOREST ROAD 3350
FairOver: BUSH CREEK
4.5 MI NW GIBBS CITY, Iron, MI
Built 1955 Load: 17.8 t ADT: 50
SPRUCE STREET
FairOver: IRON RIVER
1.3 MI SO OF US-2 BRIDGE, Iron, MI
Built 1997 Load: 24.3 t ADT: 750
FH16 FAS 300
FairOver: COOKS RUN RIVER
0.5 N US 2 ON FH 16, Iron, MI
Built 1986 Load: 26.6 t ADT: 324
4TH AVENUE
FairOver: IRON RIVER
1600 FT N OF US-2, Iron, MI
Built 1993 Load: 29.5 t ADT: 600
US-2
FairOver: COOKS RUN RIVER
5.3 MI SE OF GOGEBIC COL, Iron, MI
Built 1937 Load: 29.8 t ADT: 1,090
OLD BEECHWOOD RD
FairOver: SO BRANCH IRON RIVER
NE COR SEC 24 T43N R36W, Iron, MI
Built 2003 Load: 32.1 t ADT: 50
CO RD 424
FairOver: IRON RIVER
SO CITY LIMITS, Iron, MI
Built 1929 Load: 32.7 t ADT: 800
PARK DRIVE
FairOver: IRON RIVER
IN CASPIAN, Iron, MI
Built 1992 Load: 32.7 t ADT: 500
US-2
FairOver: FORTUNE LAKE OUTLET
4.3MI W OF CRYSTAL FALLS, Iron, MI
Built 1942 Load: 33.7 t ADT: 3,653
MANSFIELD RD
FairOver: MICHIGAMME RIVER
3.5 MI NW COLONY CORNERS, Iron, MI
Built 2006 Load: 34.0 t ADT: 179
US-141
FairOver: PAINT RIVER
4.0 MI NW OF CRYSTAL FALL, Iron, MI
Built 1970 Load: 34.7 t ADT: 3,039
FOREST ROAD 3270
FairOver: SOUTH BRANCH PAINT RIVER
4 MI N OF GOLDEN LAKE, Iron, MI
Built 1957 Load: 34.7 t ADT: 50
14TH AVENUE
FairOver: IRON RIVER
1200 FT EAST CO RD 653, Iron, MI
Built 1985 Load: 35.9 t ADT: 75
US-2 US-141
FairOver: DUNN CREEK
1.8 MI S OF CRYSTAL FALLS, Iron, MI
Built 1936 Load: 36.0 t ADT: 3,031
US-2 (ADAMS ST)
FairOver: IRON RIVER
400 FT NO OF S GENESEE, Iron, MI
Built 1997 Load: 36.0 t ADT: 7,655
US-2 US-141
FairOver: BRULE RIVER
AT WISCONSIN STATE LINE, Iron, MI
Built 1941 Load: 36.3 t ADT: 3,031
CASPIAN ROAD
FairOver: IRON RIVER
IN CASPIAN, Iron, MI
Built 2003 Load: 37.3 t ADT: 678
M-189
FairOver: BRULE RIVER
AT WISCONSIN STATE LINE, Iron, MI
Built 1989 Load: 37.9 t ADT: 1,094
PARKS FARM RD.
FairOver: HEMLOCK RIVER
0.25 MI.WEST OF USH141, Iron, MI
Built 1989 Load: 39.9 t ADT: 110
TOWNLINE RD
FairOver: HEMLOCK RIVER
0.5 MI WEST US-141, Iron, MI
Built 1989 Load: 40.8 t ADT: 50
FENCE RIVER RD
FairOver: FENCE RIVER
7.0 MI WEST M-95, Iron, MI
Built 1991 Load: 41.5 t ADT: 28
CO RD 657 FH57
FairOver: SO BR PAINT RIVER
1.0 MI W OF GIBBS CITY, Iron, MI
Built 1987 Load: 44.4 t ADT: 129
M-69
FairOver: PAINT RIVER
IN CRYSTAL FALLS, Iron, MI
Built 1924 Load: 44.7 t ADT: 3,080
16TH AVE(HOMER RD)
FairOver: IRON RIVER
500 FT N OF W. ADAMS, Iron, MI
Built 1995 Load: 46.0 t ADT: 1,345
US-141
FairOver: E BR NET RIVER
4.0 MI S OF BARAGA COL, Iron, MI
Built 1961 Load: 49.2 t ADT: 1,046
FAIRBANKS ROAD
FairOver: PAINT RIVER
1 MI N OF M-69 PAINT R B, Iron, MI
Built 1998 Load: 53.1 t ADT: 500
CO ROAD 643
FairOver: PAINT RIVER
SEC 36 T44N R34W IRON CO, Iron, MI
Built 1959 Load: 67.7 t ADT: 630
US-141
FairOver: HEMLOCK RIVER
PARK FARMS RD (AMASA), Iron, MI
Built 1971 Load: 97.2 t ADT: 1,046
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.