County profile · official public datasets

Terrebonne County, LA

215 public highway bridges tracked in the FHWA National Bridge Inventory: 42.3% rated Good, 47% Fair, 10.7% Poor.

215
Public bridges
42.3%
Good condition
10.7%
Poor condition

The verdict

According to the Federal Highway Administration's 2024 National Bridge Inventory.

Terrebonne County posts a higher-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.

33rd
of 64 on Poor share
10.7%
Poor-condition share
215
public highway bridges
1983
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.

Terrebonne County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Terrebonne County ranks #33 of 64 Louisiana counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 10.7%). Terrebonne County, Louisiana contains 215 public highway bridges. Roughly 42.3% are rated “Good,” 47% “Fair,” and 10.7% “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.

Total bridges

215

Public highway bridges in Terrebonne County

Good condition

42.3%

91 of 215 rated 7-9

Fair condition

47%

101 of 215 rated 5-6

Poor condition

10.7%

23 of 215 rated 4 or below

In-state Poor-share rank

#33 of 64

Among Louisiana counties with 5+ bridges, lower share ranks better

Condition distribution

Share of 215 NBI-tracked bridges by lowest applicable component rating.

Good
42.3% (91)
Fair
47% (101)
Poor
10.7% (23)

Terrebonne County's Poor-condition bridges carry 81,537 vehicle crossings a day

That is 8.1% of the county's reported daily bridge traffic on 10.7% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 3,545 crossings a day against 4,595 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 215 of 215 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

37.2% of Terrebonne County's bridges have passed the 50-year mark

80 of the 215 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 42.3% 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 17.1% of the county's Poor-condition bridge traffic

N. HOLLYWOOD RD over DRAIN CANAL, built 1965, carries 13,934 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 23-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 81,537 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Terrebonne County's bridges were built

215 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1990s, when 53 of the county's bridges still in the inventory were built, which is 24.7% of those with a recorded year. That cohort is now 25 to 34 years old in the 2024 inventory. Its average build year (1983) matches the Louisiana average (1982).

Source FHWA National Bridge Inventory (year built) As of 2024 NBI release

How Terrebonne County compares with Louisiana's closest counties by inventory size

The 5 Louisiana counties nearest Terrebonne County in number of bridges, with their condition splits. Its 10.7% Poor share is the 2nd-lowest of these 6. Its average build year of 1983 against a peer-group mean of 1982 is in line with the group.

Showing the 5 closest of 63 Louisiana counties eligible for comparison.

Bridge inventory size and condition shares for Terrebonne County and the 5 Louisiana counties closest to it in inventory size
County Bridges Poor
Beauregard County 221 8.1%
Winn County 220 16.4%
Ascension County 216 13%
Terrebonne County (this page) 215 10.7%
Grant County 209 15.8%
Richland County 207 11.1%

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 Terrebonne 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 Terrebonne County, both outside Louisiana so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside LA (215 bridges here).

Similar average build year

Nearest mean year-built outside LA (1983 here).

Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.

All bridges (215)

SOUTH ST

Poor

Over: COULEE

0.004 MI W OF DEADWOOD RD, Terrebonne, LA

Built 1960 Load: 14.8 t ADT: 135

MOFFET RD

Poor

Over: CHAUVIN BAYOU

0057 LOG MI FROM IN, Terrebonne, LA

Built 1979 Load: 15.2 t ADT: 5,123

LA0024

Poor

Over: CO. CANAL (BOURG)

1.20 MI W OF LA 24, Terrebonne, LA

Built 1951 Load: 15.4 t ADT: 8,645

E WOODLAWN RANCH R

Poor

Over: GRAND CAILLOU BAYOU

0.2 MI E OF LA 57, Terrebonne, LA

Built 1980 Load: 16.5 t ADT: 4,278

Savanne Rd

Poor

Over: HANSON CANAL

00.82 N. of LA 182, Terrebonne, LA

Built 1967 Load: 16.5 t ADT: 2,200

FALGOUT CANAL RD

Poor

Over: GRAND CAILLOU BAYOU

0.04 MI W OF LA 57, Terrebonne, LA

Built 1976 Load: 17.5 t ADT: 363

LA0058

Poor

Over: DRAINAGE CANAL

.36 MI EAST OF LA 56, Terrebonne, LA

Built 1966 Load: 18.1 t ADT: 5,194

ROUSSELL ST

Poor

Over: BAYOU TERREBONNE

0.01 M W OF EAST PARK, Terrebonne, LA

Built 1979 Load: 20.1 t ADT: 2,503

LA0315

Poor

Over: FALGOUT CANAL

11.0 MI SOUTH OF LA 661, Terrebonne, LA

Built 1964 Load: 20.4 t ADT: 2,378

LA0315

Poor

Over: PROVOST BAYOU

8.6 MI SOUTH OF LA 661, Terrebonne, LA

Built 1953 Load: 21.1 t ADT: 6,715

9th St

Poor

Over: ST LOUIS CANAL

0005 LOG MI FROM INT, Terrebonne, LA

Built 1965 Load: 21.4 t ADT: 3,492

LA3197

Poor

Over: HOUMA CANAL

.4 MI EAST OF LA 182, Terrebonne, LA

Built 1938 Load: 26.3 t ADT: 119

NORTH ST

Poor

Over: CHACAHOULA CANAL

0.01M W OF DEADWOOD RD, Terrebonne, LA

Built 2011 Load: 74.5 t ADT: 135

N. HOLLYWOOD RD

Poor

Over: DRAIN CANAL

0.6 MI. W. OF LA 182, Terrebonne, LA

Built 1965 Load: 97.2 t ADT: 13,934

BRADY BRIDGE RD

Poor

Over: DU LARGE BAYOU

0.01 MI W OF LA 315, Terrebonne, LA

Built 1960 Load: 99.9 t ADT: 700
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.