County profile · official public datasets

Knox County, ME

53 public highway bridges tracked in the FHWA National Bridge Inventory: 26.4% rated Good, 54.7% Fair, 18.9% Poor.

53
Public bridges: 26.4%
Good condition: 18.9%
Poor condition

The verdict

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

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

11th
of 16 on Poor share: 18.9%
Poor-condition share: 53
public highway bridges: 1970
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.

Knox County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Knox County ranks #11 of 16 Maine counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 18.9%). Knox County, Maine contains 53 public highway bridges. Roughly 26.4% are rated “Good,” 54.7% “Fair,” and 18.9% “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

Public highway bridges in Knox County

Good condition

26.4%

14 of 53 rated 7-9

Fair condition

54.7%

29 of 53 rated 5-6

Poor condition

18.9%

10 of 53 rated 4 or below

In-state Poor-share rank

#11 of 16

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

Condition distribution

Share of 53 NBI-tracked bridges by lowest applicable component rating.

Good

26.4% (14)

Fair

54.7% (29)

Poor

18.9% (10)

Knox County's Poor-condition bridges carry 34,831 vehicle crossings a day

That is 29.4% of the county's reported daily bridge traffic on 18.9% of its bridges: Poor-condition structures carry more traffic than their share of the inventory. Each Poor bridge averages 3,483 crossings a day against 1,495 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 53 of 53 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

60.4% of Knox County's bridges have passed the 50-year mark

32 of the 53 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 26.4% 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 32.9% of the county's Poor-condition bridge traffic

MAIN ST over MEGUNTICOOK RIVER, built 1931, carries 11,473 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 10-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 34,831 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1920s

4
1930s

12
1940s

4
1950s

7
1960s

3
1970s

2
1980s

1
1990s

3
2000s

4
2010s

11
2020s

2

What this shows Construction peaked in the 1930s, when 12 of the county's bridges still in the inventory were built, which is 22.6% of those with a recorded year. That cohort is now 85 to 94 years old in the 2024 inventory. Its average build year (1970) matches the Maine average (1970).

How Knox County compares with Maine's closest counties by inventory size

The 5 Maine counties nearest Knox County in number of bridges, with their condition splits. Its 18.9% Poor share is the 4th-lowest of these 6. Its average build year of 1970 against a peer-group mean of 1968 is in line with the group.

Showing the 5 closest of 15 Maine counties eligible for comparison.

Bridge inventory size and condition shares for Knox County and the 5 Maine counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Waldo County	92	16.3%	66.3%	17.4%	1964
Piscataquis County	80	18.8%	60%	21.3%	1966
Hancock County	70	21.4%	55.7%	22.9%	1964
Sagadahoc County	64	26.6%	60.9%	12.5%	1976
Lincoln County	63	25.4%	63.5%	11.1%	1972
Knox County (this page)	53	26.4%	54.7%	18.9%	1970

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

Similar inventory size

Nearest county inventories outside ME (53 bridges here).

Cleburne County, AR · 53 bridges
Citrus County, FL · 53 bridges
Lumpkin County, GA · 53 bridges
Stewart County, GA · 53 bridges

Similar average build year

Nearest mean year-built outside ME (1970 here).

Hamilton County, OH · avg 1970 · 783 bridges
Yavapai County, AZ · avg 1970 · 543 bridges
Garfield County, OK · avg 1970 · 504 bridges
San Luis Obispo County, CA · avg 1970 · 401 bridges

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

All 53 Good 14 Fair 29 Poor 10

All bridges (53)

Sort:

Knox County Bridge Snapshot

Condition distribution

Knox County's Poor-condition bridges carry 34,831 vehicle crossings a day

60.4% of Knox County's bridges have passed the 50-year mark

One structure carries 32.9% of the county's Poor-condition bridge traffic

How Knox County compares with Maine's closest counties by inventory size

Nationwide counties with similar inventory size or average build year

Similar inventory size

Similar average build year

All bridges (53)

MAIN ST

DEPOT ST

PULPIT HARBOR RD

AUGUSTA RD

JEFFERSON RD

FITCH RD

BURKETTVILLE RD

ROCKLAND RD

MOUNT BATTIE ST

FAIRGROUNDS LN

FERRY RD

SHEPARD HILL RD

CAMDEN RD

FERRY SLIP

VINALHAVEN FERRY

MILLER RD

MIDDLE RD

WALDOBORO RD

COMMON RD

WESTERN RD

BEACHWOOD ST

INV 1301439 RD

MAIN ST

S UNION RD

ATLANTIC HWY

RAZORVILLE RD

MAIN ST

WADSWORTH ST

SKIDMORE RD

SANDY SHORES RD

FITCH RD

W MEADOW RD

ISLAND AV

WADSWORTH ST

OYSTER RIVER RD

WOTTONS MILL RD

WASHINGTON ST

PULPIT HARBOR RD

ISLAND RD

THOMPSON MEADOW DR

SPRUCE HEAD RD

WASHINGTON ST

MILL ST

RAWSON AV

WESTERN RD

MAIN ST

KNOWLTON ST

PASCAL AV

CAMDEN RD

MAIN ST

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