Total bridges
297
Public highway bridges in Monroe County
County profile · official public datasets
Monroe County, MI
297 public highway bridges tracked in the FHWA National Bridge Inventory: 30% rated Good, 54.5% Fair, 15.5% Poor.
- 297
- Public bridges
- 30%
- Good condition
- 15.5%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Monroe County posts a higher-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.
- 59th
- of 83 on Poor share
- 15.5%
- Poor-condition share
- 297
- 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.
Monroe County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Monroe County ranks #59 of 83 Michigan counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 15.5%). Monroe County, Michigan contains 297 public highway bridges. Roughly 30% are rated “Good,” 54.5% “Fair,” and 15.5% “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%
89 of 297 rated 7-9
Fair condition
54.5%
162 of 297 rated 5-6
Poor condition
15.5%
46 of 297 rated 4 or below
In-state Poor-share rank
#59 of 83
Among Michigan counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 297 NBI-tracked bridges by lowest applicable component rating.
Good 30% (89)
Fair 54.5% (162)
Poor 15.5% (46)
Monroe County's Poor-condition bridges carry 203,824 vehicle crossings a day
That is 7.9% of the county's reported daily bridge traffic on 15.5% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 4,431 crossings a day against 9,265 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 297 of 297 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
53.5% of Monroe County's bridges have passed the 50-year mark
159 of the 297 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% 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 33.3% of the county's Poor-condition bridge traffic
I-75 over CONRAIL RAISIN R FRONT, built 1955, carries 67,800 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 46-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 203,824 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Monroe County's bridges were built
297 bridges with a recorded construction year, grouped by decade
- pre-1900 1
Built before 1900
1 bridges
- 1900s 1
1900–1909
1 bridges
- 1910s 1
1910–1919
1 bridges
- 1920s 16
1920–1929
16 bridges
- 1930s 13
1930–1939
13 bridges
- 1940s 6
1940–1949
6 bridges
- 1950s
1950–1959
55 bridges
- 1960s
1960–1969
37 bridges
- 1970s
1970–1979
49 bridges
- 1980s
1980–1989
30 bridges
- 1990s 21
1990–1999
21 bridges
- 2000s
2000–2009
35 bridges
- 2010s 19
2010–2019
19 bridges
- 2020s 13
2020–2029
13 bridges
What this shows Construction peaked in the 1950s, when 55 of the county's bridges still in the inventory were built, which is 18.5% 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 Monroe County compares with Michigan's closest counties by inventory size
The 5 Michigan counties nearest Monroe County in number of bridges, with their condition splits. Its 15.5% Poor share is the 4th-lowest of these 6. Its average build year of 1974 against a peer-group mean of 1979 is 5 years older.
Showing the 5 closest of 82 Michigan counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| St. Clair County | 327 | 41.3% | 50.5% | 8.3% | 1985 |
| Saginaw County | 315 | 28.9% | 52.7% | 18.4% | 1979 |
| Monroe County (this page) | 297 | 30% | 54.5% | 15.5% | 1974 |
| Berrien County | 272 | 27.6% | 66.5% | 5.9% | 1979 |
| Washtenaw County | 262 | 23.3% | 56.5% | 20.2% | 1975 |
| Ottawa County | 254 | 40.9% | 52.8% | 6.3% | 1977 |
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 Monroe 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 Monroe County, both outside Michigan so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside MI (297 bridges here).
- Crawford County, KS · 297 bridges
- Kingfisher County, OK · 297 bridges
- Sarasota County, FL · 298 bridges
- Rutherford County, NC · 298 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.
All bridges (297)
M-125
FairOver: PLUM CREEK
1.1 MI SW OF M-50, Monroe, MI
Built 1985 Load: 16.8 t ADT: 18,902
STRASBURG ROAD
FairOver: PITTS DRAIN
0.25 MI N OF DUNBAR ROAD, Monroe, MI
Built 1975 Load: 22.0 t ADT: 1,530
MINX ROAD
FairOver: LOCKWOOD DRAIN
0.2 MI N OF YARGERVILLE R, Monroe, MI
Built 1987 Load: 22.4 t ADT: 40
BAY CREEK ROAD
FairOver: LITTLE LAKE CREEK
1 MI N OF SUMMIT STREET, Monroe, MI
Built 1955 Load: 23.0 t ADT: 140
SHEICK ROAD
FairOver: SANDY CREEK
0.15 MI S OF BLUEBUSH RD, Monroe, MI
Built 1985 Load: 23.0 t ADT: 230
RAISINVILLE ROAD
FairOver: MASON RUN DRAIN
0.1 MI. S. OF STEWART RD., Monroe, MI
Built 1963 Load: 23.6 t ADT: 2,490
BLOHM ROAD
FairOver: PLUM CREEK
0.65 MI W OF RAISINVILLE, Monroe, MI
Built 1990 Load: 24.3 t ADT: 20
IDA CENTER RD
FairOver: US-23
4.6 MI N OF US-223, Monroe, MI
Built 1958 Load: 25.3 t ADT: 1,030
LENAWEE CO.LINE RD
FairOver: S BRANCH MACON DRAIN
.85 MI N BREWER RD, Monroe, MI
Built 1950 Load: 25.3 t ADT: 100
BREWER RD
FairOver: US-23
0.7 MI S OF M-50, Monroe, MI
Built 1959 Load: 26.6 t ADT: 250
JEFFS ROAD
FairOver: OTTAWA LAKE OUTLET
0.1 MI. S. OF STERNS RD., Monroe, MI
Built 1964 Load: 27.5 t ADT: 191
US-24
FairOver: RAISIN RIVER & ELM AVE
IN MONROE, Monroe, MI
Built 1988 Load: 27.9 t ADT: 27,951
MILWAUKEE RD
FairOver: US-23
3.7 MI N OF M-50, Monroe, MI
Built 1961 Load: 28.5 t ADT: 290
SHERMAN ROAD
FairOver: SALINE RIVER
0.1 MI E OF WELLS ROAD, Monroe, MI
Built 1981 Load: 28.5 t ADT: 500
LENAWEE CO LINE RD
FairOver: N DR MID BR MACON R
1.0 MI NO OF M 50, Monroe, MI
Built 1994 Load: 28.8 t ADT: 110
NORTH DIXIE HWY
FairOver: I-75
@ OLD M-50, Monroe, MI
Built 1956 Load: 29.5 t ADT: 15,000
OSTRANDER RD
FairOver: SALINE RIVER
2.7 MI E OF ANN ARBOR RD, Monroe, MI
Built 1970 Load: 29.8 t ADT: 770
SHERMAN RD
FairOver: US-23
1.6 MI S OF WASHTENAW COL, Monroe, MI
Built 1961 Load: 30.5 t ADT: 957
US-223
FairOver: US-23
AT US-23 US-223 INTRCHNG, Monroe, MI
Built 1959 Load: 30.5 t ADT: 8,550
STOWELL RD
FairOver: MACON RIVER
1.85 MI N OF DUNDEE, Monroe, MI
Built 1964 Load: 30.5 t ADT: 1,300
DOUGLAS RD
FairOver: HALFWAY CREEK
.45 MI NO OF STATE LINE, Monroe, MI
Built 1975 Load: 30.8 t ADT: 4,326
PETERSBURG ROAD
FairOver: NORTH MACON CREEK
0.3 MI S OF REDMAN ROAD, Monroe, MI
Built 1983 Load: 30.8 t ADT: 170
DIXON RD
FairOver: US-23
2.2 MI S OF M-50, Monroe, MI
Built 1959 Load: 31.1 t ADT: 980
STRASBURG ROAD
FairOver: OTTER CREEK
1 MI N OF YARGERVILLE RD, Monroe, MI
Built 1935 Load: 31.1 t ADT: 965
M-50
FairOver: RIVER RAISIN
IN DUNDEE MONROE ST, Monroe, MI
Built 1937 Load: 31.8 t ADT: 9,360
IDA MAYBEE RD
FairOver: RIVER RAISIN
4.15 MI N OF IDA WEST RD, Monroe, MI
Built 1958 Load: 32.1 t ADT: 2,666
STRASBURG RD
FairOver: LOCKWOOD DRAIN
0.1 MI N OF S OTTER CK RD, Monroe, MI
Built 1935 Load: 32.4 t ADT: 937
NORTH DIXIE HWY
FairOver: WALKER DRAIN
3.55 MI N OF I-75, Monroe, MI
Built 1988 Load: 32.4 t ADT: 8,479
OAKVILLE WALTZ RD
FairOver: SWAN CREEK
1.4 MI E OF RAWSONVILLE, Monroe, MI
Built 1989 Load: 32.4 t ADT: 2,126
E ELM AVENUE
FairOver: MASON RUN DRAIN
IN MONROE, Monroe, MI
Built 1927 Load: 32.4 t ADT: 5,435
HICKORY CREEK DR
FairOver: INDIAN CREEK OVERFLOW
.5 MI E OF LEWIS AVE, Monroe, MI
Built 2004 Load: 32.4 t ADT: 60
CONE RD
FairOver: MILAN-MACON DRAIN
.35 MI E OF LENAWEE CO LI, Monroe, MI
Built 1970 Load: 32.7 t ADT: 290
DUNBAR ROAD
FairOver: PITTS CREEK
0.5 MI E OF GEIGER ROAD, Monroe, MI
Built 1980 Load: 32.7 t ADT: 2,550
DOTY ROAD
FairOver: N BR WILLOW RUN
1.9 MI N OF N CUSTER RD, Monroe, MI
Built 1981 Load: 32.7 t ADT: 180
GRAFTON ROAD
FairOver: SWAN CREEK
6.5 MI N OF US 24, Monroe, MI
Built 1926 Load: 32.7 t ADT: 3,030
MAXWELL ROAD
FairOver: LITTLE SWAN CREEK
0.1 MI S OF SIGLER ROAD, Monroe, MI
Built 1986 Load: 32.7 t ADT: 188
GEIGER ROAD
FairOver: LOCKWOOD DRAIN
.04 MI N OF IDA CENTER RD, Monroe, MI
Built 1984 Load: 32.7 t ADT: 155
MINX ROAD
FairOver: N BR OTTER CREEK
1.5 MI N OF YARGERVILLE, Monroe, MI
Built 1988 Load: 32.7 t ADT: 80
PLATT ROAD
FairOver: MILAN CENTER DRAIN
0.1 MI S OF CONE ROAD, Monroe, MI
Built 1980 Load: 32.7 t ADT: 50
WABASH STREET
FairOver: SALINE RIVER
IN MILAN, Monroe, MI
Built 1937 Load: 32.7 t ADT: 4,100
ROESSLER STREET
FairOver: RIVER RAISIN
IN MONROE, Monroe, MI
Built 1970 Load: 32.7 t ADT: 9,200
RAISINVILLE RD
FairOver: RIVER RAISIN
.10 MI NORTH OF M 50, Monroe, MI
Built 1968 Load: 33.0 t ADT: 5,940
DAVIS ROAD
FairOver: LITTLE RIVER RAISIN
0.2 MI S OF BREWER ROAD, Monroe, MI
Built 1979 Load: 33.0 t ADT: 171
RAWSONVILLE ROAD
FairOver: STONY CREEK
0.1 MI S OF HIVON ROAD, Monroe, MI
Built 1984 Load: 33.0 t ADT: 230
FAR ROAD
FairOver: NORTH MACON DRAIN
0.2 MI S OF DAY ROAD, Monroe, MI
Built 1990 Load: 33.4 t ADT: 20
HISER ROAD
FairOver: MIDDLE BRANCH MACON DRAI
0.1 MI N OF M 50, Monroe, MI
Built 1990 Load: 33.6 t ADT: 54
I-75 NB
FairOver: PLUM CREEK
IN MONROE, Monroe, MI
Built 1955 Load: 33.7 t ADT: 31,883
I-75 SB
FairOver: PLUM CREEK
IN MONROE, Monroe, MI
Built 1955 Load: 33.7 t ADT: 31,883
GRAFTON ROAD
FairOver: N BRANCH SWAN CREEK
7.6 MI N OF US 24, Monroe, MI
Built 1926 Load: 33.7 t ADT: 2,730
FAR ROAD
FairOver: MACON - MILAN DRAIN
0.4 MI N OF COUPER ROAD, Monroe, MI
Built 1968 Load: 33.7 t ADT: 37
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.