Total bridges
53
Public highway bridges in Alger County
County profile · official public datasets
Alger County, MI
53 public highway bridges tracked in the FHWA National Bridge Inventory: 30.2% rated Good, 58.5% Fair, 11.3% Poor.
- 53
- Public bridges
- 30.2%
- Good condition
- 11.3%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Alger 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.
- 43rd
- of 83 on Poor share
- 11.3%
- Poor-condition share
- 53
- public highway bridges
- 1956
- 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.
Alger County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Alger County ranks #43 of 83 Michigan counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 11.3%). Alger County, Michigan contains 53 public highway bridges. Roughly 30.2% are rated “Good,” 58.5% “Fair,” and 11.3% “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.
Good condition
30.2%
16 of 53 rated 7-9
Fair condition
58.5%
31 of 53 rated 5-6
Poor condition
11.3%
6 of 53 rated 4 or below
In-state Poor-share rank
#43 of 83
Among Michigan counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 53 NBI-tracked bridges by lowest applicable component rating.
Good 30.2% (16)
Fair 58.5% (31)
Poor 11.3% (6)
Alger County's Poor-condition bridges carry 1,705 vehicle crossings a day
That is 3.1% of the county's reported daily bridge traffic on 9.6% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 341 crossings a day against 353 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 52 of 53 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
66% of Alger County's bridges have passed the 50-year mark
35 of the 53 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 30.2% 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 96.2% of the county's Poor-condition bridge traffic
US-41 over W BR WHITEFISH RIVER, built 1936, carries 1,640 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 6-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 1,705 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Alger County's bridges were built
53 bridges with a recorded construction year, grouped by decade
- 1900s 1
1900–1909
1 bridges
- 1910s
1910–1919
7 bridges
- 1920s
1920–1929
5 bridges
- 1930s
1930–1939
8 bridges
- 1940s
1940–1949
9 bridges
- 1950s
1950–1959
4 bridges
- 1970s 3
1970–1979
3 bridges
- 1980s 3
1980–1989
3 bridges
- 1990s 3
1990–1999
3 bridges
- 2000s
2000–2009
8 bridges
- 2010s 2
2010–2019
2 bridges
What this shows Construction peaked in the 1940s, when 9 of the county's bridges still in the inventory were built, which is 17% of those with a recorded year. That cohort is now 75 to 84 years old in the 2024 inventory. Its average build year is 1956, 20 years older than the Michigan average of 1976.
How Alger County compares with Michigan's closest counties by inventory size
The 5 Michigan counties nearest Alger County in number of bridges, with their condition splits. Its 11.3% Poor share is the 3rd-lowest of these 6. Its average build year of 1956 against a peer-group mean of 1972 is 16 years older.
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 |
| Iron County | 54 | 20.4% | 59.3% | 20.4% | 1967 |
| Schoolcraft County | 54 | 27.8% | 66.7% | 5.6% | 1967 |
| Alger County (this page) | 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 Alger 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 Alger County, both outside Michigan so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside MI (53 bridges here).
- Cleburne County, AR · 53 bridges
- Citrus County, FL · 53 bridges
- Lumpkin County, GA · 53 bridges
- Stewart County, GA · 53 bridges
Similar average build year
Nearest mean year-built outside MI (1956 here).
- Philadelphia County, PA · avg 1956 · 585 bridges
- Cochise County, AZ · avg 1956 · 501 bridges
- Hampden County, MA · avg 1956 · 428 bridges
- Stanislaus County, CA · avg 1956 · 386 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
Good-condition bridges (16)
STAR SIDING ROAD
GoodOver: STAR CREEK
1.5 MI N OF M-28, Alger, MI
Built 1993 Load: 21.1 t ADT: 5
M-28
GoodOver: LAUGHING WHITEFISH RIVER
3.2 MI E OF MARQUETTE COL, Alger, MI
Built 1939 Load: 26.9 t ADT: 3,093
H-13 FEDERAL HY 13
GoodOver: LITTLE INDIAN RIVER
8 MI N OF COUNTY LINE, Alger, MI
Built 1947 Load: 27.9 t ADT: 394
FOREST LAKE R FH79
GoodOver: AU TRAIN RIVER
1.44 MI S OF AU TRAIN, Alger, MI
Built 1977 Load: 30.0 t ADT: 500
OLD US-41
GoodOver: WHITEFISH RIVER
0.75 MI S OF TRENARY, Alger, MI
Built 1989 Load: 32.7 t ADT: 50
OLD SENEY ROAD
GoodOver: SUCKER RIVER
2 MI S GRAND MARAIS FIELD, Alger, MI
Built 2012 Load: 35.0 t ADT: 20
PETER WHITE ROAD
GoodOver: LAUGHING WHITEFISH RIVER
1.25 MI S OF DEERTON, Alger, MI
Built 2001 Load: 38.6 t ADT: 73
ROCKRIVER ROAD
GoodOver: ROCK RIVER
1.1 MI S OF M-28, Alger, MI
Built 2007 Load: 39.7 t ADT: 145
FOREST ROAD
GoodOver: SUCKER RIVER
4 MI E OF GRAND MARAIS, Alger, MI
Built 2001 Load: 44.6 t ADT: 20
HOY ROAD
GoodOver: SCOTT CREEK
MATHIAS TWP SEC 7, Alger, MI
Built 2003 Load: 45.7 t ADT: 50
COUNTY RD(H-58)
GoodOver: HURRICANE RIVER
BURT TWP SEC 10, Alger, MI
Built 2010 Load: 52.5 t ADT: 675
NORTH POINT DRIVE
GoodOver: LAUGHING WHITEFISH RIVER
1.5 MI N OF DEERTON, Alger, MI
Built 2006 Load: 55.7 t ADT: 50
DEERTON ROAD
GoodOver: LAUGHING WHITEFISH RIVER
AT DEERTON, Alger, MI
Built 2006 Load: 59.0 t ADT: 135
USFS RTE 2473
GoodOver: BIG INDIAN RIVER
0.5 MI W OF MIRROR LAKE, Alger, MI
Built 2005 Load: 72.6 t ADT: 50
ROUND LAKE RD FH78
GoodOver: STURGEON RIVER
2 MI E OF W BR LAKE RD, Alger, MI
Built 2001 Load: 86.8 t ADT: 191
ROUND LAKE RD FH78
GoodOver: WEST BRANCH CREEK
0.25 MI N W BRANCH LAKE, Alger, MI
Built 1949 Load: 97.2 t ADT: 191
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.