Total bridges
171
Public highway bridges in Miami County
County profile · official public datasets
Miami County, IN
171 public highway bridges tracked in the FHWA National Bridge Inventory: 34.5% rated Good, 57.9% Fair, 7.6% Poor.
- 171
- Public bridges
- 34.5%
- Good condition
- 7.6%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Miami County pairs a higher-than-median Poor-condition share among rated counties in the state with an older average build year than the state inventory.
- 72nd
- of 92 on Poor share
- 7.6%
- Poor-condition share
- 171
- public highway bridges
- 1966
- 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.
Miami County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Miami County ranks #72 of 92 Indiana counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 7.6%). Miami County, Indiana contains 171 public highway bridges. Roughly 34.5% are rated “Good,” 57.9% “Fair,” and 7.6% “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
34.5%
59 of 171 rated 7-9
Fair condition
57.9%
99 of 171 rated 5-6
Poor condition
7.6%
13 of 171 rated 4 or below
In-state Poor-share rank
#72 of 92
Among Indiana counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 171 NBI-tracked bridges by lowest applicable component rating.
Good 34.5% (59)
Fair 57.9% (99)
Poor 7.6% (13)
Miami County's Poor-condition bridges carry 3,035 vehicle crossings a day
That is 0.9% of the county's reported daily bridge traffic on 7.1% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 253 crossings a day against 2,859 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 170 of 171 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
54.4% of Miami County's bridges have passed the 50-year mark
93 of the 171 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 34.5% 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 29.7% of the county's Poor-condition bridge traffic
CR 1050 EAST over BIG PIPE CREEK, built 1930, carries 900 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 13-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 3,035 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Miami County's bridges were built
171 bridges with a recorded construction year, grouped by decade
- pre-1900 1
Built before 1900
1 bridges
- 1900s 4
1900–1909
4 bridges
- 1910s 2
1910–1919
2 bridges
- 1920s 11
1920–1929
11 bridges
- 1930s
1930–1939
26 bridges
- 1940s 8
1940–1949
8 bridges
- 1950s 6
1950–1959
6 bridges
- 1960s
1960–1969
21 bridges
- 1970s
1970–1979
33 bridges
- 1980s
1980–1989
18 bridges
- 1990s
1990–1999
16 bridges
- 2000s
2000–2009
18 bridges
- 2010s 5
2010–2019
5 bridges
- 2020s 2
2020–2029
2 bridges
What this shows Construction peaked in the 1970s, when 33 of the county's bridges still in the inventory were built, which is 19.3% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year is 1966, 12 years older than the Indiana average of 1978.
How Miami County compares with Indiana's closest counties by inventory size
The 5 Indiana counties nearest Miami County in number of bridges, with their condition splits. Its 7.6% Poor share is the 3rd-lowest of these 6. Its average build year of 1966 against a peer-group mean of 1978 is 12 years older.
Showing the 5 closest of 91 Indiana counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Washington County | 174 | 44.8% | 52.9% | 2.3% | 1976 |
| Newton County | 172 | 41.9% | 56.4% | 1.7% | 1981 |
| Pike County | 172 | 50.6% | 39% | 10.5% | 1978 |
| Miami County (this page) | 171 | 34.5% | 57.9% | 7.6% | 1966 |
| Lawrence County | 165 | 32.1% | 58.2% | 9.7% | 1981 |
| Jennings County | 163 | 39.9% | 50.3% | 9.8% | 1973 |
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 Miami 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 Miami County, both outside Indiana so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside IN (171 bridges here).
- Crenshaw County, AL · 171 bridges
- Lincoln County, LA · 171 bridges
- Sanilac County, MI · 171 bridges
- Pine County, MN · 171 bridges
Similar average build year
Nearest mean year-built outside IN (1966 here).
- Butler County, KS · avg 1966 · 591 bridges
- Grafton County, NH · avg 1966 · 544 bridges
- Queens County, NY · avg 1966 · 514 bridges
- Lehigh County, PA · avg 1966 · 381 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
Poor-condition bridges (13)
CR 100 EAST
PoorOver: EEL RIVER
0.80 S OF SR 16, Miami, IN
Built 1915 Load: 0.0 t
CR 700 NORTH
PoorOver: FLOWERS CREEK
0.20 W OF WARSAW TRL, Miami, IN
Built 1910 Load: 0.0 t ADT: 200
CR 950 NORTH
PoorOver: EEL RIVER
0.10 E OF PONY FARM ROAD, Miami, IN
Built 1903 Load: 0.0 t ADT: 100
WATER STREET
PoorOver: LITTLE PIPE CREEK
0.30 E OF CR 1000 E, Miami, IN
Built 1930 Load: 9.8 t ADT: 300
CR 1050 EAST
PoorOver: BIG PIPE CREEK
0.40 N OF CR 1100 S, Miami, IN
Built 1930 Load: 13.3 t ADT: 900
CR 1200 SOUTH
PoorOver: RUSSELL DITCH
0.50 W OF US 31, Miami, IN
Built 1930 Load: 14.7 t ADT: 100
CR 100 WEST
PoorOver: LITTLE WEESAU CREEK
0.20 S OF CR 800 N, Miami, IN
Built 1940 Load: 14.7 t ADT: 150
CR 300 WEST
PoorOver: RIFE CREEK
0.00 N OF CR 250 S, Miami, IN
Built 1935 Load: 15.7 t ADT: 625
CR 450 EAST
PoorOver: DANIEL CREEK
0.40 N OF WABASH ROAD, Miami, IN
Built 1925 Load: 17.4 t ADT: 100
PARK DRIVE
PoorOver: SCHOOLMAN DITCH
0.20 S OF GRAHAM ST, Miami, IN
Built 1935 Load: 25.5 t ADT: 235
CR 1400 NORTH
PoorOver: SQUIRREL CREEK
0.10 W OF CR 400 E, Miami, IN
Built 1945 Load: 31.1 t ADT: 125
CR 600 EAST
PoorOver: SQUIRREL CREEK
0.00 S of CR 1300 N, Miami, IN
Built 1920 Load: 32.7 t ADT: 100
CR 1200 SOUTH
PoorOver: LITTLE PIPE CREEK
0.40 W OF CR 1050 E, Miami, IN
Built 1930 Load: 32.7 t ADT: 100
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.