County profile · official public datasets

Boone County, KY

138 public highway bridges tracked in the FHWA National Bridge Inventory: 40.6% rated Good, 55.1% Fair, 4.3% Poor.

138
Public bridges: 40.6%
Good condition: 4.3%
Poor condition

The verdict

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

Boone County posts a top-quartile lowest Poor-condition share among rated counties in the state across mid-size county bridge inventory.

Top 23%
lowest Poor share in state: 4.3%
Poor-condition share: 138
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.

Boone County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Boone County ranks #28 of 120 Kentucky counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 4.3%). Boone County, Kentucky contains 138 public highway bridges. Roughly 40.6% are rated “Good,” 55.1% “Fair,” and 4.3% “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

138

Public highway bridges in Boone County

Good condition

40.6%

56 of 138 rated 7-9

Fair condition

55.1%

76 of 138 rated 5-6

Poor condition

4.3%

6 of 138 rated 4 or below

In-state Poor-share rank

#28 of 120

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

Condition distribution

Share of 138 NBI-tracked bridges by lowest applicable component rating.

Good

40.6% (56)

Fair

55.1% (76)

Poor

4.3% (6)

Boone County's Poor-condition bridges carry 21,417 vehicle crossings a day

That is 1.1% of the county's reported daily bridge traffic on 4.3% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 3,570 crossings a day against 9,201 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 138 of 138 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

36.2% of Boone County's bridges have passed the 50-year mark

50 of the 138 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 40.6% 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 43.4% of the county's Poor-condition bridge traffic

KY-842 over NS (CNO&TP) SYSTEM, built 1982, carries 9,286 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 21,417 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1900s

2
1930s

6
1940s

2
1950s

12
1960s

15
1970s

24
1980s

18
1990s

29
2000s

16
2010s

10
2020s

4

What this shows Construction peaked in the 1990s, when 29 of the county's bridges still in the inventory were built, which is 21% 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 Kentucky average (1978).

How Boone County compares with Kentucky's closest counties by inventory size

The 5 Kentucky counties nearest Boone County in number of bridges, with their condition splits. Its 4.3% Poor share is the 3rd-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 119 Kentucky counties eligible for comparison.

Bridge inventory size and condition shares for Boone County and the 5 Kentucky counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Kenton County	142	39.4%	52.8%	7.7%	1978
Boone County (this page)	138	40.6%	55.1%	4.3%	1981
Shelby County	137	10.2%	81.8%	8%	1982
Lincoln County	136	13.2%	83.8%	2.9%	1976
Logan County	135	17.8%	78.5%	3.7%	1978
Knott County	134	35.8%	51.5%	12.7%	1981

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

Similar inventory size

Nearest county inventories outside KY (138 bridges here).

Santa Cruz County, AZ · 138 bridges
Hancock County, IA · 138 bridges
Ralls County, MO · 138 bridges
Scurry County, TX · 138 bridges

Similar average build year

Nearest mean year-built outside KY (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.

All 138 Good 56 Fair 76 Poor 6

All bridges (138)

Sort:

Boone County Bridge Snapshot

Condition distribution

Boone County's Poor-condition bridges carry 21,417 vehicle crossings a day

36.2% of Boone County's bridges have passed the 50-year mark

One structure carries 43.4% of the county's Poor-condition bridge traffic

How Boone County compares with Kentucky'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 (138)

I-75 RAMP

BIG BONE CHURCH RD

WEAVER ROAD

CR-1066V

MINEOLA PIKE

KY-18

KY-14

MARY GRUBBS HWY NC

I-275 WB

KY-8

KY 237

I-75 NC

HOPEFULL CHURCH

KY-16

I-75

KY-1292

KY-8

I-75

KY-1292

STEPHENSON MILL RD

I-71

KY-20

KY-338

SHADY HOLLOW LN

I-75

I-275

KY-8

WATERLOO RD

BROWN RD

BOONE AIRE RD

RICE PIKE

TREETOP LN

WOODCREEK DR

GRAVES RD

CR-1004

POINT PLEASANT RD

KY-536

I-75

KY-20

WESTBROOK BLVD.

BIG BONE LICK RD

KY-338

KY-18

KY-20

SADDLE RIDGE DR

RIVER RD

ASHBY FORK RD

MEADOW CREEK DR

ORLEANS BLVD

THORNWILDE DR

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