Total bridges
190
Public highway bridges in Clinton County
County profile · official public datasets
Clinton County, IL
190 public highway bridges tracked in the FHWA National Bridge Inventory: 56.3% rated Good, 36.3% Fair, 7.4% Poor.
- 190
- Public bridges
- 56.3%
- Good condition
- 7.4%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Clinton County posts a better-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.
- Top 48%
- lowest Poor share in state
- 7.4%
- Poor-condition share
- 190
- public highway bridges
- 1976
- 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.
Clinton County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Clinton County ranks #49 of 102 Illinois counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 7.4%). Clinton County, Illinois contains 190 public highway bridges. Roughly 56.3% are rated “Good,” 36.3% “Fair,” and 7.4% “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
56.3%
107 of 190 rated 7-9
Fair condition
36.3%
69 of 190 rated 5-6
Poor condition
7.4%
14 of 190 rated 4 or below
In-state Poor-share rank
#49 of 102
Among Illinois counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 190 NBI-tracked bridges by lowest applicable component rating.
Good 56.3% (107)
Fair 36.3% (69)
Poor 7.4% (14)
Clinton County's Poor-condition bridges carry 7,900 vehicle crossings a day
That is 1.9% of the county's reported daily bridge traffic on 7.4% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 564 crossings a day against 2,478 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 190 of 190 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
44.2% of Clinton County's bridges have passed the 50-year mark
84 of the 190 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 56.3% 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 34.2% of the county's Poor-condition bridge traffic
ALBERS RD/FAS 785 over GRASSY BRANCH, built 1973, carries 2,700 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 14-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 7,900 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Clinton County's bridges were built
190 bridges with a recorded construction year, grouped by decade
- 1900s 7
1900–1909
7 bridges
- 1910s 2
1910–1919
2 bridges
- 1920s 5
1920–1929
5 bridges
- 1930s 10
1930–1939
10 bridges
- 1940s 10
1940–1949
10 bridges
- 1950s 5
1950–1959
5 bridges
- 1960s
1960–1969
16 bridges
- 1970s
1970–1979
39 bridges
- 1980s
1980–1989
24 bridges
- 1990s
1990–1999
34 bridges
- 2000s
2000–2009
24 bridges
- 2010s 11
2010–2019
11 bridges
- 2020s 3
2020–2029
3 bridges
What this shows Construction peaked in the 1970s, when 39 of the county's bridges still in the inventory were built, which is 20.5% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year (1976) matches the Illinois average (1979).
How Clinton County compares with Illinois's closest counties by inventory size
The 5 Illinois counties nearest Clinton County in number of bridges, with their condition splits. Its 7.4% Poor share is the 4th-lowest of these 6. Its average build year of 1976 against a peer-group mean of 1979 is in line with the group.
Showing the 5 closest of 101 Illinois counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Jo Daviess County | 193 | 46.1% | 44% | 9.8% | 1973 |
| De Witt County | 192 | 57.3% | 37% | 5.7% | 1980 |
| Union County | 192 | 54.7% | 41.7% | 3.6% | 1981 |
| Clinton County (this page) | 190 | 56.3% | 36.3% | 7.4% | 1976 |
| Lawrence County | 185 | 36.2% | 41.1% | 22.7% | 1975 |
| Saline County | 185 | 71.4% | 23.8% | 4.9% | 1985 |
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 Clinton 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 Clinton County, both outside Illinois so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside IL (190 bridges here).
- Wapello County, IA · 190 bridges
- Webster County, IA · 190 bridges
- Bienville County, LA · 190 bridges
- Lincoln County, MT · 190 bridges
Similar average build year
Nearest mean year-built outside IL (1976 here).
- Marion County, IN · avg 1976 · 958 bridges
- Mohave County, AZ · avg 1976 · 641 bridges
- Comanche County, OK · avg 1976 · 593 bridges
- Prince George's County, MD · avg 1976 · 576 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
Poor-condition bridges (14)
TR 137A
PoorOver: LOST CK
2MIS.E. HUEY, Clinton, IL
Built 1916 Load: 4.5 t ADT: 50
TR 109/OLD STATE R
PoorOver: BEAVER CREEK
1.25 MI N BECKMEYER, Clinton, IL
Built 1930 Load: 11.7 t ADT: 75
SHATTUC RD/TR 206
PoorOver: BREWSTER CREEK
4.5 MI N. SHATTUC, Clinton, IL
Built 1966 Load: 13.3 t ADT: 200
TR 56/LAKE BRANCH
PoorOver: LAKE BRANCH
2 MI NW BREESE, Clinton, IL
Built 1966 Load: 17.5 t ADT: 25
TR 137A
PoorOver: PRAIRIE CREEK
1 MI SE HUEY, Clinton, IL
Built 1942 Load: 17.8 t ADT: 100
FAS 1781
PoorOver: BOND BRANCH
1.0 MI N CARLYLE, Clinton, IL
Built 1963 Load: 23.0 t ADT: 950
FAS 788
PoorOver: PRAIRE CREEK
1.0 MI N HOFFMANN, Clinton, IL
Built 1955 Load: 24.3 t ADT: 725
TR 175
PoorOver: PRAIRIE BRANCH
2 MI NE HOFFMANN, Clinton, IL
Built 1940 Load: 25.3 t ADT: 300
TR 198/LADUE ROAD
PoorOver: COLES CREEK
.5 MI S. EAST FORK T, Clinton, IL
Built 1901 Load: 25.3 t ADT: 25
ILL 177
PoorOver: QUEENS LAKE
W CL NEW MEMPHIS, Clinton, IL
Built 1922 Load: 30.5 t ADT: 2,000
ALBERS RD/FAS 785
PoorOver: GRASSY BRANCH
0.5 MI S OF ALBERS, Clinton, IL
Built 1973 Load: 35.0 t ADT: 2,700
EMERALD RD
PoorOver: TRIB TO BEAVER CRK
1570E EMERALD RD, Clinton, IL
Built 1996 Load: 37.6 t ADT: 350
COURT ROAD/TR177
PoorOver: LAKE BRANCH
1 MI NW OF ALBERS, Clinton, IL
Built 1992 Load: 38.9 t ADT: 225
TR 133/ SANDOVAL R
PoorOver: LOST CREEK BRANCH
S. SHATTUC, Clinton, IL
Built 1948 Load: 73.2 t ADT: 175
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.