Total bridges
82
Public highway bridges in St. Charles County
County profile · official public datasets
St. Charles County, LA
82 public highway bridges tracked in the FHWA National Bridge Inventory: 59.8% rated Good, 39% Fair, 1.2% Poor.
- 82
- Public bridges
- 59.8%
- Good condition
- 1.2%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
St. Charles County posts a top-5% lowest Poor-condition share among rated counties in the state across rated county bridge inventory.
- Top 2%
- lowest Poor share in state
- 1.2%
- Poor-condition share
- 82
- public highway bridges
- 1981
- 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.
St. Charles County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, St. Charles County ranks #1 of 64 Louisiana counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 1.2%). St. Charles County, Louisiana contains 82 public highway bridges. Roughly 59.8% are rated “Good,” 39% “Fair,” and 1.2% “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
59.8%
49 of 82 rated 7-9
Fair condition
39%
32 of 82 rated 5-6
Poor condition
1.2%
1 of 82 rated 4 or below
In-state Poor-share rank
#1 of 64
Among Louisiana counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 82 NBI-tracked bridges by lowest applicable component rating.
Good 59.8% (49)
Fair 39% (32)
Poor 1.2% (1)
St. Charles County's Poor-condition bridges carry 1,544 vehicle crossings a day
That is 0.1% of the county's reported daily bridge traffic on 1.3% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 1,544 crossings a day against 20,653 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 79 of 82 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
19.5% of St. Charles County's bridges have passed the 50-year mark
16 of the 82 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 59.8% 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 100% of the county's Poor-condition bridge traffic
LA0631 over DRAIN CANAL, built 1962, carries 1,544 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 1-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 1,544 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When St. Charles County's bridges were built
82 bridges with a recorded construction year, grouped by decade
- 1930s 2
1930–1939
2 bridges
- 1940s 6
1940–1949
6 bridges
- 1950s 2
1950–1959
2 bridges
- 1960s 4
1960–1969
4 bridges
- 1970s
1970–1979
15 bridges
- 1980s
1980–1989
22 bridges
- 1990s
1990–1999
25 bridges
- 2000s 3
2000–2009
3 bridges
- 2010s 3
2010–2019
3 bridges
What this shows Construction peaked in the 1990s, when 25 of the county's bridges still in the inventory were built, which is 30.5% of those with a recorded year. That cohort is now 25 to 34 years old in the 2024 inventory. Its average build year (1981) matches the Louisiana average (1982).
How St. Charles County compares with Louisiana's closest counties by inventory size
The 5 Louisiana counties nearest St. Charles County in number of bridges, with their condition splits. Its 1.2% Poor share is the 1st-lowest of these 6. Its average build year of 1981 against a peer-group mean of 1979 is in line with the group.
Showing the 5 closest of 63 Louisiana counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| West Carroll County | 88 | 23.9% | 69.3% | 6.8% | 1982 |
| St. Charles County (this page) | 82 | 59.8% | 39% | 1.2% | 1981 |
| Iberville County | 80 | 33.8% | 51.3% | 15% | 1975 |
| West Baton Rouge County | 73 | 32.9% | 52.1% | 15.1% | 1969 |
| Catahoula County | 70 | 45.7% | 45.7% | 8.6% | 1984 |
| Assumption County | 68 | 48.5% | 41.2% | 10.3% | 1984 |
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 St. Charles 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 St. Charles County, both outside Louisiana so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside LA (82 bridges here).
- Murray County, GA · 82 bridges
- Gallatin County, IL · 82 bridges
- Thomas County, KS · 82 bridges
- Nicholas County, KY · 82 bridges
Similar average build year
Nearest mean year-built outside LA (1981 here).
- Franklin County, OH · avg 1981 · 922 bridges
- Greenville County, SC · avg 1981 · 635 bridges
- Montgomery County, OH · avg 1981 · 632 bridges
- McLean County, IL · avg 1981 · 624 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
Fair-condition bridges (32)
LA0631
FairOver: BAYOU DESALLEMAND
.4 MI WEST OF LA 632, St. Charles, LA
Built 1935 Load: 8.1 t ADT: 1,834
I0310
FairOver: LA 3127 & I-310
2.9 MI EAST OF LA 3160, St. Charles, LA
Built 1986 Load: 15.9 t ADT: 15,642
I0310
FairOver: MISSISSIPPI RIVER
4.4 MI S OF US 61, St. Charles, LA
Built 1983 Load: 22.7 t ADT: 47,396
I0310
FairOver: US 61/RR/SWAMP/LA 626
0.41 M SOUTH OF I-10, St. Charles, LA
Built 1992 Load: 25.3 t ADT: 20,850
US0061
FairOver: BONNET CARRE
.7 MI WEST OF LA 48, St. Charles, LA
Built 1935 Load: 25.4 t ADT: 25,051
I0310
FairOver: RAMPS/US 61
0.2 M NORTH OF US 61, St. Charles, LA
Built 1992 Load: 28.1 t ADT: 15,642
I0310
FairOver: ICG.RR RAMP E F &H LA4
5.14 MI S I-10 I-310 JCT, St. Charles, LA
Built 1983 Load: 28.1 t ADT: 47,396
US0090
FairOver: SELLERS CANAL
5.6 MI EAST OF LA 633, St. Charles, LA
Built 1940 Load: 29.0 t ADT: 25,051
I0310
FairOver: US 61/RR/SWAMP/LA 626
0.41 M SOUTH OF I-10, St. Charles, LA
Built 1992 Load: 29.0 t ADT: 20,850
I0310
FairOver: RAMPS/US 61
0.2 1M NORTH OF US 61, St. Charles, LA
Built 1992 Load: 29.0 t ADT: 15,642
I0310
FairOver: RAMPS/RR/CANAL/US 61
0.25 M SOUTH OF US 61, St. Charles, LA
Built 1992 Load: 29.0 t ADT: 15,642
I0310
FairOver: RAMPS/RR/CANAL/US 61
0.10 M NORTH OF US 61, St. Charles, LA
Built 1992 Load: 29.0 t ADT: 15,642
US0090
FairOver: B DESALLEMANDS
.4 MI WEST OF LA 362, St. Charles, LA
Built 1961 Load: 29.9 t ADT: 20,956
US0090
FairOver: B DESALLEMANDS
.4 MI WEST OF LA 362, St. Charles, LA
Built 1961 Load: 29.9 t ADT: 17,200
US0090
FairOver: DRAIN CANAL
4.3 MI EAST OF LA 633, St. Charles, LA
Built 1940 Load: 29.9 t ADT: 25,051
I0310
FairOver: RAMP"C" FROM I 310 SB
.36 MI SOUTH OF LA 18, St. Charles, LA
Built 1979 Load: 29.9 t ADT: 47,396
I0310
FairOver: M. P. RR
4.9 MI S OF US 61, St. Charles, LA
Built 1979 Load: 30.8 t ADT: 47,396
I0310
FairOver: I-310 OVER LA 3127
1.57 MI. N. OF US 90, St. Charles, LA
Built 1986 Load: 30.8 t ADT: 40,204
US0090
FairOver: SELLERS CANAL
5.6 MI EAST OF LA 633, St. Charles, LA
Built 1953 Load: 31.8 t ADT: 49,920
I0310
FairOver: DRAIN CANAL
0.8 MILES SOUTH OF HALES, St. Charles, LA
Built 1984 Load: 32.4 t ADT: 40,204
US0090
FairOver: DRAIN CANAL
4.3 MI EAST OF LA 633, St. Charles, LA
Built 1953 Load: 32.7 t ADT: 49,920
I0310
FairOver: RAMP"C"FROM I 310 SB
.36 MI SOUTH OF LA 18, St. Charles, LA
Built 1979 Load: 32.7 t ADT: 29,468
LA3127
FairOver: UNION CARBIDE CANAL
.6 MI EAST OF LA 3142, St. Charles, LA
Built 1975 Load: 33.4 t ADT: 6,703
I0310
FairOver: RAMP "A"
.2 MI SOUTH OF LA 18, St. Charles, LA
Built 1979 Load: 34.3 t ADT: 15,642
I0310
FairOver: S.P. R.R. & LA 631
.5 MI NORTH OF US 90, St. Charles, LA
Built 1986 Load: 34.5 t ADT: 29,468
US0061
FairOver: BONNET CARRE SPILLWAY
.7 MI WEST OF LA 48, St. Charles, LA
Built 1984 Load: 35.4 t ADT: 23,719
I0010
FairOver: SWAMP (EMERGENCY X-OVER)
3.0 MI WEST OF I-310, St. Charles, LA
Built 1992 Load: 35.4 t ADT: 29,468
I0010
FairOver: BONNET CARRE SPILLWAY
1.9 MI EAST OF I-55, St. Charles, LA
Built 1972 Load: 38.1 t ADT: 48,723
I0010
FairOver: BONNET CARRE SPILLWAY
1.9 MI EAST OF I-55, St. Charles, LA
Built 1972 Load: 38.1 t ADT: 32,050
LA0306
FairOver: GRAND BAYOU
2.0 MI SOUTH OF LA 632, St. Charles, LA
Built 1984 Load: 40.8 t ADT: 370
LA3127
FairOver: VIAL CANAL
.9 MI EAST OF LA 3160, St. Charles, LA
Built 1975 Load: 43.5 t ADT: 6,703
LA3127
FairOver: EIGHTY ARPENT CANAL
3.6 MI EAST OF LA 3160, St. Charles, LA
Built 1975 Load: 43.5 t ADT: 6,703
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.