Total bridges
346
Public highway bridges in Dubuque County
County profile · official public datasets
Dubuque County, IA
346 public highway bridges tracked in the FHWA National Bridge Inventory: 50.6% rated Good, 40.8% Fair, 8.7% Poor.
- 346
- Public bridges
- 50.6%
- Good condition
- 8.7%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Dubuque County pairs a top-quartile lowest Poor-condition share among rated counties in the state with a newer average build year than the state inventory.
- Top 13%
- lowest Poor share in state
- 8.7%
- Poor-condition share
- 346
- public highway bridges
- 1989
- 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.
Dubuque County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Dubuque County ranks #13 of 99 Iowa counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 8.7%). Dubuque County, Iowa contains 346 public highway bridges. Roughly 50.6% are rated “Good,” 40.8% “Fair,” and 8.7% “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
50.6%
175 of 346 rated 7-9
Fair condition
40.8%
141 of 346 rated 5-6
Poor condition
8.7%
30 of 346 rated 4 or below
In-state Poor-share rank
#13 of 99
Among Iowa counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 346 NBI-tracked bridges by lowest applicable component rating.
Good 50.6% (175)
Fair 40.8% (141)
Poor 8.7% (30)
Dubuque County's Poor-condition bridges carry 9,093 vehicle crossings a day
That is 1.2% of the county's reported daily bridge traffic on 8.7% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 303 crossings a day against 2,143 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 345 of 346 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
23.1% of Dubuque County's bridges have passed the 50-year mark
80 of the 346 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 50.6% 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 20.6% of the county's Poor-condition bridge traffic
OLD IA 966 over OVER CC RR, built 1936, carries 1,876 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 30-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 9,093 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Dubuque County's bridges were built
346 bridges with a recorded construction year, grouped by decade
- pre-1900 1
Built before 1900
1 bridges
- 1900s 5
1900–1909
5 bridges
- 1910s 2
1910–1919
2 bridges
- 1920s 8
1920–1929
8 bridges
- 1930s 10
1930–1939
10 bridges
- 1940s 12
1940–1949
12 bridges
- 1950s 11
1950–1959
11 bridges
- 1960s 16
1960–1969
16 bridges
- 1970s 30
1970–1979
30 bridges
- 1980s
1980–1989
50 bridges
- 1990s
1990–1999
49 bridges
- 2000s
2000–2009
50 bridges
- 2010s
2010–2019
84 bridges
- 2020s 18
2020–2029
18 bridges
What this shows Construction peaked in the 2010s, when 84 of the county's bridges still in the inventory were built, which is 24.3% of those with a recorded year. That cohort is now 5 to 14 years old in the 2024 inventory. Its average build year is 1989, 10 years newer than the Iowa average of 1979.
How Dubuque County compares with Iowa's closest counties by inventory size
The 5 Iowa counties nearest Dubuque County in number of bridges, with their condition splits. Its 8.7% Poor share is the 2nd-lowest of these 6. Its average build year of 1989 against a peer-group mean of 1976 is 13 years newer.
Showing the 5 closest of 98 Iowa counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Clinton County | 372 | 66.7% | 30.4% | 3% | 1986 |
| Johnson County | 372 | 39.5% | 50.3% | 10.2% | 1979 |
| Fayette County | 362 | 35.1% | 40.3% | 24.6% | 1974 |
| Dubuque County (this page) | 346 | 50.6% | 40.8% | 8.7% | 1989 |
| Winneshiek County | 342 | 37.1% | 45.3% | 17.5% | 1967 |
| Tama County | 337 | 34.4% | 31.2% | 34.4% | 1976 |
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 Dubuque 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 Dubuque County, both outside Iowa so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside IA (346 bridges here).
- Macon County, IL · 346 bridges
- Whitman County, WA · 347 bridges
- Navarro County, TX · 345 bridges
- Fillmore County, MN · 348 bridges
Similar average build year
Nearest mean year-built outside IA (1989 here).
- Harris County, TX · avg 1989 · 4,029 bridges
- Mecklenburg County, NC · avg 1989 · 746 bridges
- Buffalo County, NE · avg 1989 · 459 bridges
- Brazos County, TX · avg 1989 · 370 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
Fair-condition bridges (141)
LOCAL
FairOver: CURRAN BRANCH
087010104, Dubuque, IA
Built 1938 Load: 33.3 t ADT: 40
US 20
FairOver: MISS. RIVER HWY & RR
IN DUBUQUE, Dubuque, IA
Built 1943 Load: 33.6 t ADT: 17,700
FREMONT AVE
FairOver: CATFISH CREEK CC RR
N.E. OF KELLY LANE, Dubuque, IA
Built 1996 Load: 34.0 t ADT: 5,041
FETTKETHER LANE
FairOver: NO FORK LITTLE MAQUOKETA
090E12812, Dubuque, IA
Built 2017 Load: 35.0 t ADT: 20
LOCAL
FairOver: CREEK
088010902, Dubuque, IA
Built 1900 Load: 35.1 t ADT: 49
OLD MILL RD
FairOver: CATFISH CREEK
N.W. OF ROCKDALE RD, Dubuque, IA
Built 1978 Load: 35.3 t ADT: 5,395
MONROE ST NE
FairOver: CREEK
000000000, Dubuque, IA
Built 1929 Load: 36.3 t ADT: 424
US 61 & 151
FairOver: PEOSTA CHL & CITY ST
0.2 mi. N. of E 11th St., Dubuque, IA
Built 1991 Load: 36.7 t ADT: 22,300
SB US 61 & 151
FairOver: IA 946 & CITY STS & RR
0.3 MI. S OF JCT. U.S. 20, Dubuque, IA
Built 1990 Load: 37.0 t ADT: 6,150
IA 3
FairOver: LITTLE MAQUOKETA RIVER
0.4 mi. N of N Jct SR D10, Dubuque, IA
Built 1947 Load: 37.2 t ADT: 5,100
FM
FairOver: LYTLE CREEK
087E22903, Dubuque, IA
Built 1992 Load: 37.2 t ADT: 260
CREEKWOOD DR
FairOver: CATFISH CREEK
W. OF MANSON RD., Dubuque, IA
Built 2006 Load: 37.3 t ADT: 549
US 52
FairOver: N FORK MAQUOKETA RIVER
0.1 mi. S of Jct. SR C64, Dubuque, IA
Built 1985 Load: 38.7 t ADT: 3,990
IA 3
FairOver: N FORK LITTLE MAQUOKETA
5.9 mi. W of Jct. SR C9Y, Dubuque, IA
Built 1967 Load: 38.8 t ADT: 1,680
US 151
FairOver: US 61
AT JUNCTION OF U.S. 61, Dubuque, IA
Built 1970 Load: 39.2 t ADT: 160
US 20 EB US 52 SB
FairOver: Y 17 (EPWORTH)
At Jct. of SR Y17, Dubuque, IA
Built 1988 Load: 39.7 t ADT: 6,750
FM
FairOver: MIDDLE MAQUOKETA RIVER
090E13204, Dubuque, IA
Built 1974 Load: 40.2 t ADT: 350
DUTCH LANE RD
FairOver: WHITE WATER CREEK
088E11702, Dubuque, IA
Built 2012 Load: 40.8 t ADT: 151
12TH ST. N.E.
FairOver: HEWETTS CREEK
12TH ST NE-HEWITT CREEK, Dubuque, IA
Built 1995 Load: 41.1 t ADT: 1,778
NB US 61 & 151
FairOver: IA 946 & CITY STS & RR
0.3 MI. S OF JCT. U.S. 20, Dubuque, IA
Built 1990 Load: 42.4 t ADT: 6,100
US 61 & 151
FairOver: MISSISSIPPI RIVER ISLAND
IN NORTH DUBUQUE, Dubuque, IA
Built 1982 Load: 42.6 t ADT: 20,400
EB US 20
FairOver: N FORK MAQUOKETA RIVER
0.6 MI. W OF JCT IA 136, Dubuque, IA
Built 1986 Load: 42.6 t ADT: 5,400
US 61/151 SB
FairOver: 4TH 5TH WHITE ST
0.6 mi. N of US 20, Dubuque, IA
Built 1992 Load: 42.8 t ADT: 12,300
US 151 NB
FairOver: WHITE WATER CREEK
1.8 mi. S of Jct. SR D53, Dubuque, IA
Built 1971 Load: 43.3 t ADT: 9,300
1 ST AVE. W
FairOver: N FORK MAQUOKETA RIVER
000000000, Dubuque, IA
Built 1979 Load: 43.4 t ADT: 5,495
BUNCOMBE RD
FairOver: BUNCOMBE CREEK
087E21403, Dubuque, IA
Built 2001 Load: 43.7 t ADT: 34
LOCAL
FairOver: BUNCOMBE CREEK
087E21504, Dubuque, IA
Built 1993 Load: 43.7 t ADT: 20
MANSON RD
FairOver: CATFISH CREEK
N.E. OF CREEKWOOD DR, Dubuque, IA
Built 2002 Load: 44.7 t ADT: 340
FM
FairOver: JOHNS CREEK
087011604, Dubuque, IA
Built 1991 Load: 45.4 t ADT: 590
MILLVILLE RD
FairOver: STREAM
089013403, Dubuque, IA
Built 2017 Load: 46.3 t ADT: 20
IA 136
FairOver: BR DURIEN CREEK
0.1 mi. N of SR D39, Dubuque, IA
Built 1985 Load: 47.2 t ADT: 2,520
FM
FairOver: N. FORK LITTLE MAQUOKETA
090E11902, Dubuque, IA
Built 2001 Load: 48.2 t ADT: 240
UNIVERSITY AVE
FairOver: NORTH FORK CATFISH CREEK
E. OF JOHN F KENNEDY RD, Dubuque, IA
Built 2006 Load: 51.8 t ADT: 4,131
FM
FairOver: PRAIRIE CREEK
087E12304, Dubuque, IA
Built 1991 Load: 52.9 t ADT: 650
FM
FairOver: JOHNS CREEK
087011703, Dubuque, IA
Built 2001 Load: 52.9 t ADT: 130
FM
FairOver: CATFISH CREEK
088E21604, Dubuque, IA
Built 1998 Load: 52.9 t ADT: 450
GRAF RD
FairOver: LITTLE MAQUOKETA RIVER
089E13203, Dubuque, IA
Built 2006 Load: 52.9 t ADT: 560
FM
FairOver: WHITE WATER CREEK
088013511, Dubuque, IA
Built 1996 Load: 53.5 t ADT: 530
FM
FairOver: WHITE WATER CREEK
088013603, Dubuque, IA
Built 1996 Load: 53.5 t ADT: 530
LOCAL
FairOver: CREEK
089022701, Dubuque, IA
Built 1988 Load: 60.9 t ADT: 97
US 20
FairOver: N BRANCH CATFISH CREEK
1.7 mi. E of Jct. IA 32, Dubuque, IA
Built 1939 Load: 99.9 t ADT: 33,600
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.