County profile · official public datasets

Mercer County, MO

137 public highway bridges tracked in the FHWA National Bridge Inventory: 44.5% rated Good, 36.5% Fair, 19% Poor.

137
Public bridges
44.5%
Good condition
19%
Poor condition

The verdict

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

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

107th
of 115 on Poor share
19%
Poor-condition share
137
public highway bridges
1976
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.

Mercer County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Mercer County ranks #107 of 115 Missouri counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 19%). Mercer County, Missouri contains 137 public highway bridges. Roughly 44.5% are rated “Good,” 36.5% “Fair,” and 19% “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

137

Public highway bridges in Mercer County

Good condition

44.5%

61 of 137 rated 7-9

Fair condition

36.5%

50 of 137 rated 5-6

Poor condition

19%

26 of 137 rated 4 or below

In-state Poor-share rank

#107 of 115

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

Condition distribution

Share of 137 NBI-tracked bridges by lowest applicable component rating.

Good
44.5% (61)
Fair
36.5% (50)
Poor
19% (26)

Mercer County's Poor-condition bridges carry 3,420 vehicle crossings a day

That is 13% of the county's reported daily bridge traffic on 19% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 132 crossings a day against 75 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 137 of 137 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

40.9% of Mercer County's bridges have passed the 50-year mark

56 of the 137 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 44.5% 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 55.1% of the county's Poor-condition bridge traffic

US 136 E over GRAND RVR OVRFL, built 1971, carries 1,883 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 26-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 3,420 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Mercer County's bridges were built

137 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 2000s, when 31 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 15 to 24 years old in the 2024 inventory. Its average build year (1976) matches the Missouri average (1979).

Source FHWA National Bridge Inventory (year built) As of 2024 NBI release

How Mercer County compares with Missouri's closest counties by inventory size

The 5 Missouri counties nearest Mercer County in number of bridges, with their condition splits. Its 19% Poor share is the 4th-lowest of these 6. Its average build year of 1976 against a peer-group mean of 1973 is in line with the group.

Showing the 5 closest of 114 Missouri counties eligible for comparison.

Bridge inventory size and condition shares for Mercer County and the 5 Missouri counties closest to it in inventory size
County Bridges Poor
Miller County 142 10.6%
St. Clair County 139 19.4%
Ralls County 138 7.2%
Mercer County (this page) 137 19%
Benton County 135 20.7%
Howard County 133 8.3%

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

Similar inventory size

Nearest county inventories outside MO (137 bridges here).

Similar average build year

Nearest mean year-built outside MO (1976 here).

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

All 137 Good 61 Fair 50 Poor 26

Poor-condition bridges (26)

AIREDALE AVE

Poor

Over: TRIB W FK LITTLE R

S 3 T 66 N R 25 W, Mercer, MO

Built 1910 Load: 0.0 t ADT: 20

BEETLE ST

Poor

Over: LIT WELDON RVR

S 16 T 66 N R 24 W, Mercer, MO

Built 1910 Load: 0.0 t ADT: 15

FORBES ST

Poor

Over: BR OF MEDICINE CR

S 30 T 65 N R 22 W, Mercer, MO

Built 1904 Load: 0.0 t ADT: 30

ICEBERG RD

Poor

Over: MARTIN CR

S 22 T 64 N R 25 W, Mercer, MO

Built 1920 Load: 0.0 t ADT: 15

COLONY LOOP

Poor

Over: TRIB OF WELDON BR

S 27 T 66 N R 24 W, Mercer, MO

Built 1950 Load: 2.7 t ADT: 15

DANUBE ST

Poor

Over: BRUSHY CR

S 5 T 65 N R 25 W, Mercer, MO

Built 1971 Load: 2.7 t ADT: 15

EBONY ST

Poor

Over: BRUSH CR

S 18 T 65 N R 25 W, Mercer, MO

Built 1900 Load: 2.7 t ADT: 5

HELIUM RD

Poor

Over: TRIB LIT MEDICINE

S 16 T 64 N R 22 W, Mercer, MO

Built 1950 Load: 4.5 t ADT: 30

JEWELL ST

Poor

Over: WEST HONEY CR

S 5 T 63 N R 23 W, Mercer, MO

Built 1994 Load: 7.2 t ADT: 35

INKWELL ST

Poor

Over: WEST HONEY CR

S 29 T 64 N R 23 W, Mercer, MO

Built 1940 Load: 9.0 t ADT: 20

RT D E

Poor

Over: WEST MUDDY CR

S 36 T 64 N R 25 W, Mercer, MO

Built 1935 Load: 9.0 t ADT: 119

CONCORD ST

Poor

Over: MUDDY CR

S 28 T 66 N R 23 W, Mercer, MO

Built 1910 Load: 9.9 t ADT: 5

HARMONICA RD

Poor

Over: UP RR

S 34 T 65 N R 24 W, Mercer, MO

Built 1901 Load: 9.9 t ADT: 35

DELTA ST

Poor

Over: BIG BR

S 1 T 65 N R 25 W, Mercer, MO

Built 1900 Load: 9.9 t ADT: 5

GEMSTONE AVE

Poor

Over: WEST HONEY CR

S 4 T 64 N R 23 W, Mercer, MO

Built 1930 Load: 11.7 t ADT: 15

JOGGER AVE

Poor

Over: BR OF W MUDDY CRK

S 6 T 63 N R 24 W, Mercer, MO

Built 1930 Load: 11.7 t ADT: 20

GARNER ST

Poor

Over: W MUDDY CR

S 6 T 64 N R 24 W, Mercer, MO

Built 1920 Load: 13.5 t ADT: 15

BISON ST

Poor

Over: LIT MUDDY CR

S 9 T 66 N R 23 W, Mercer, MO

Built 1994 Load: 14.4 t ADT: 35

RT JJ E

Poor

Over: HONEY CR

S 8 T 63 N R 23 W, Mercer, MO

Built 1957 Load: 14.4 t ADT: 67

RT E E

Poor

Over: W HONEY CR

S 4 T 64 N R 23 W, Mercer, MO

Built 1932 Load: 14.4 t ADT: 309

BRANT ST E

Poor

Over: UP RR

S 19 T 66 N R 23 W, Mercer, MO

Built 1900 Load: 15.3 t ADT: 218

RT E E

Poor

Over: W MEDICINE CK

S 28 T 64 N R 22 W, Mercer, MO

Built 1971 Load: 18.0 t ADT: 439

ARCTIC ST

Poor

Over: LIT MUDDY CR

S 28 T 67 N R 23 W, Mercer, MO

Built 2005 Load: 18.0 t ADT: 10

US 136 E

Poor

Over: GRAND RVR OVRFL

S 28 T 65 N R 24 W, Mercer, MO

Built 1971 Load: 27.9 t ADT: 1,883

FOGHORN ST

Poor

Over: BR LIT MEDICINE CR

S 35 T 65 N R 23 W, Mercer, MO

Built 1940 Load: 30.6 t ADT: 5

BADGER ST

Poor

Over: COAL CR

S 16 T 66 N R 25 W, Mercer, MO

Built 1989 Load: 39.6 t ADT: 40

Read our methodology - how this data is sourced, computed, and verified.

Related

Browse all → | Rankings →
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.