Total bridges
293
Public highway bridges in Boone County
County profile · official public datasets
Boone County, IN
293 public highway bridges tracked in the FHWA National Bridge Inventory: 39.9% rated Good, 55.3% Fair, 4.8% Poor.
- 293
- Public bridges
- 39.9%
- Good condition
- 4.8%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Boone County posts a better-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.
- Top 50%
- lowest Poor share in state
- 4.8%
- Poor-condition share
- 293
- public highway bridges
- 1974
- 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 #46 of 92 Indiana counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 4.8%). Boone County, Indiana contains 293 public highway bridges. Roughly 39.9% are rated “Good,” 55.3% “Fair,” and 4.8% “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
39.9%
117 of 293 rated 7-9
Fair condition
55.3%
162 of 293 rated 5-6
Poor condition
4.8%
14 of 293 rated 4 or below
In-state Poor-share rank
#46 of 92
Among Indiana counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 293 NBI-tracked bridges by lowest applicable component rating.
Good 39.9% (117)
Fair 55.3% (162)
Poor 4.8% (14)
Boone County's Poor-condition bridges carry 16,858 vehicle crossings a day
That is 1% of the county's reported daily bridge traffic on 4.8% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 1,204 crossings a day against 4,560 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 292 of 293 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
50.9% of Boone County's bridges have passed the 50-year mark
149 of the 293 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 39.9% 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 44.5% of the county's Poor-condition bridge traffic
SR 32 over FINLEY CREEK, built 1958, carries 7,502 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 14-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 16,858 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Boone County's bridges were built
293 bridges with a recorded construction year, grouped by decade
- pre-1900 2
Built before 1900
2 bridges
- 1900s 3
1900–1909
3 bridges
- 1910s 4
1910–1919
4 bridges
- 1920s 15
1920–1929
15 bridges
- 1930s
1930–1939
23 bridges
- 1940s 15
1940–1949
15 bridges
- 1950s 13
1950–1959
13 bridges
- 1960s
1960–1969
51 bridges
- 1970s
1970–1979
28 bridges
- 1980s
1980–1989
33 bridges
- 1990s
1990–1999
34 bridges
- 2000s
2000–2009
30 bridges
- 2010s 20
2010–2019
20 bridges
- 2020s
2020–2029
22 bridges
What this shows Construction peaked in the 1960s, when 51 of the county's bridges still in the inventory were built, which is 17.4% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year (1974) matches the Indiana average (1978).
How Boone County compares with Indiana's closest counties by inventory size
The 5 Indiana counties nearest Boone County in number of bridges, with their condition splits. Its 4.8% Poor share is the 4th-lowest of these 6. Its average build year of 1974 against a peer-group mean of 1974 is in line with the group.
Showing the 5 closest of 91 Indiana counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Madison County | 301 | 44.5% | 52.5% | 3% | 1978 |
| Vigo County | 296 | 44.9% | 50.7% | 4.4% | 1977 |
| Boone County (this page) | 293 | 39.9% | 55.3% | 4.8% | 1974 |
| Knox County | 290 | 40% | 55.2% | 4.8% | 1976 |
| Putnam County | 290 | 30.3% | 51% | 18.6% | 1963 |
| Grant County | 280 | 38.6% | 59.6% | 1.8% | 1975 |
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 Indiana so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside IN (293 bridges here).
- Delaware County, IA · 293 bridges
- Hocking County, OH · 293 bridges
- Franklin County, PA · 294 bridges
- Bedford County, TN · 294 bridges
Similar average build year
Nearest mean year-built outside IN (1974 here).
- Knox County, TN · avg 1974 · 588 bridges
- Summit County, OH · avg 1974 · 563 bridges
- Onondaga County, NY · avg 1974 · 472 bridges
- Orange County, NY · avg 1974 · 472 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
Poor-condition bridges (14)
WIND HAVEN LANE
PoorOver: PRAIRIE CREEK
00.01 E I-65, Boone, IN
Built 1925 Load: 21.2 t ADT: 20
MDL JAMESTOWN RD
PoorOver: CUNNINGHAM DITCH
00.30 N OF CR 400 S, Boone, IN
Built 1930 Load: 21.7 t ADT: 120
CR 300S
PoorOver: JACKSON RUN
00.65 W OF CR 875 E, Boone, IN
Built 1940 Load: 22.5 t ADT: 2,023
HAZELRIGG ROAD
PoorOver: DEER CREEK
01.10 W OF CR 350 W, Boone, IN
Built 1935 Load: 22.7 t ADT: 230
CR 875W
PoorOver: WALNUT FORK SUGAR CR
00.90 N OF CR 100 S, Boone, IN
Built 1925 Load: 24.5 t ADT: 120
CR 100S
PoorOver: PRAIRIE CREEK
01.30 W CR 300 E, Boone, IN
Built 1920 Load: 24.9 t ADT: 850
US 52 WB
PoorOver: I-65 SB/NB
01.89 N SR 32, Boone, IN
Built 1970 Load: 26.2 t ADT: 4,664
CR 400E
PoorOver: BROWNS WONDER CREEK
00.70 N OF CR 100 N, Boone, IN
Built 1940 Load: 26.5 t ADT: 120
SR 38
PoorOver: STOKER DITCH
04.75 E US 421, Boone, IN
Built 1966 Load: 26.9 t ADT: 329
CR 600E
PoorOver: MOUNTS RUN
00.30 N OF CR 200 N, Boone, IN
Built 1930 Load: 30.1 t ADT: 260
CR 600W
PoorOver: W FORK BIG WALNUT CREEK
00.90 N OF CR 750 S, Boone, IN
Built 1980 Load: 30.5 t ADT: 200
SR 32
PoorOver: FINLEY CREEK
01.24 E US 421, Boone, IN
Built 1958 Load: 31.1 t ADT: 7,502
CR 1000E
PoorOver: BIG EAGLE CREEK
00.40 N OF SR 32, Boone, IN
Built 1925 Load: 31.8 t ADT: 300
CR 900W
PoorOver: LITTLE SUGAR CREEK
00.75 N OF SR 32, Boone, IN
Built 1960 Load: 42.4 t ADT: 120
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.