County profile · official public datasets

Marion County, TN

177 public highway bridges tracked in the FHWA National Bridge Inventory: 53.7% rated Good, 42.9% Fair, 3.4% Poor.

177
Public bridges: 53.7%
Good condition: 3.4%
Poor condition

The verdict

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

Marion County pairs a better-than-median Poor-condition share among rated counties in the state with an older average build year than the state inventory.

Top 43%
lowest Poor share in state: 3.4%
Poor-condition share: 177
public highway bridges: 1971
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.

Marion County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Marion County ranks #41 of 95 Tennessee counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 3.4%). Marion County, Tennessee contains 177 public highway bridges. Roughly 53.7% are rated “Good,” 42.9% “Fair,” and 3.4% “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.

Total bridges

177

Public highway bridges in Marion County

Good condition

53.7%

95 of 177 rated 7-9

Fair condition

42.9%

76 of 177 rated 5-6

Poor condition

3.4%

6 of 177 rated 4 or below

In-state Poor-share rank

#41 of 95

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

Condition distribution

Share of 177 NBI-tracked bridges by lowest applicable component rating.

Good

53.7% (95)

Fair

42.9% (76)

Poor

3.4% (6)

Marion County's Poor-condition bridges carry 117,609 vehicle crossings a day

That is 7.1% of the county's reported daily bridge traffic on 3.4% of its bridges: Poor-condition structures carry more traffic than their share of the inventory. Each Poor bridge averages 19,602 crossings a day against 8,117 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 177 of 177 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

54.2% of Marion County's bridges have passed the 50-year mark

96 of the 177 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 53.7% 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 44.3% of the county's Poor-condition bridge traffic

I24 over SEQUATCHIE RIVER, built 1965, carries 52,102 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 6-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 117,609 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1920s

13
1930s

8
1940s

12
1950s

9
1960s

49
1970s

12
1980s

40
1990s

24
2000s

1
2010s

8
2020s

1

What this shows Construction peaked in the 1960s, when 49 of the county's bridges still in the inventory were built, which is 27.7% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year is 1971, 6 years older than the Tennessee average of 1977.

How Marion County compares with Tennessee's closest counties by inventory size

The 5 Tennessee counties nearest Marion County in number of bridges, with their condition splits. Its 3.4% Poor share is the 2nd-lowest of these 6. Its average build year of 1971 against a peer-group mean of 1978 is 7 years older.

Showing the 5 closest of 94 Tennessee counties eligible for comparison.

Bridge inventory size and condition shares for Marion County and the 5 Tennessee counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Henry County	187	39%	56.7%	4.3%	1978
Montgomery County	186	36.6%	57.5%	5.9%	1979
Marion County (this page)	177	53.7%	42.9%	3.4%	1971
Anderson County	175	25.1%	71.4%	3.4%	1974
Macon County	169	69.8%	25.4%	4.7%	1983
Stewart County	168	56.5%	43.5%	0%	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 Marion 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 Marion County, both outside Tennessee so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside TN (177 bridges here).

Hale County, AL · 177 bridges
Macon County, AL · 177 bridges
Washington County, AL · 177 bridges
Seminole County, FL · 177 bridges

Similar average build year

Nearest mean year-built outside TN (1971 here).

Wayne County, MI · avg 1971 · 1,026 bridges
Baltimore County, MD · avg 1971 · 783 bridges
Washington County, PA · avg 1971 · 655 bridges
Linn County, OR · avg 1971 · 566 bridges

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

All 177 Good 95 Fair 76 Poor 6

Fair-condition bridges (76)

Sort:

Marion County Bridge Snapshot

Condition distribution

Marion County's Poor-condition bridges carry 117,609 vehicle crossings a day

54.2% of Marion County's bridges have passed the 50-year mark

One structure carries 44.3% of the county's Poor-condition bridge traffic

How Marion County compares with Tennessee's closest counties by inventory size

Nationwide counties with similar inventory size or average build year

Similar inventory size

Similar average build year

Fair-condition bridges (76)

NFA A505

NFA A628

NFA 1106 (SA 5809)

NFA 1106 (SA 5809)

NFA A550

I24

I24

I24

I24

NFA A541

FAS 2

NFA 1407 (SA 5807)

FAS 2

FAP 27

NFA 1131

FAP 27

FAS 283

FAP 27

FAP 28

FAP 28

FAS 134

FAS 156

FAS 156

FAS 156

FAS 156

I24

Related