County profile · official public datasets

Monroe County, FL

100 public highway bridges tracked in the FHWA National Bridge Inventory: 34% rated Good, 59% Fair, 7% Poor.

100
Public bridges
34%
Good condition
7%
Poor condition

The verdict

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

Monroe 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.

54th
of 67 on Poor share
7%
Poor-condition share
100
public highway bridges
1978
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.

Monroe County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Monroe County ranks #54 of 67 Florida counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 7%). Monroe County, Florida contains 100 public highway bridges. Roughly 34% are rated “Good,” 59% “Fair,” and 7% “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

100

Public highway bridges in Monroe County

Good condition

34%

34 of 100 rated 7-9

Fair condition

59%

59 of 100 rated 5-6

Poor condition

7%

7 of 100 rated 4 or below

In-state Poor-share rank

#54 of 67

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

Condition distribution

Share of 100 NBI-tracked bridges by lowest applicable component rating.

Good
34% (34)
Fair
59% (59)
Poor
7% (7)

Monroe County's Poor-condition bridges carry 9,482 vehicle crossings a day

That is 1% of the county's reported daily bridge traffic on 6.1% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 1,580 crossings a day against 12,022 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 99 of 100 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

38% of Monroe County's bridges have passed the 50-year mark

38 of the 100 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% 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 33.6% of the county's Poor-condition bridge traffic

Card Sound Road over Tubbys Creek, built 1969, carries 3,182 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 7-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 9,482 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Monroe County's bridges were built

100 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1980s, when 36 of the county's bridges still in the inventory were built, which is 36% of those with a recorded year. That cohort is now 35 to 44 years old in the 2024 inventory. Its average build year is 1978, 5 years older than the Florida average of 1983.

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

How Monroe County compares with Florida's closest counties by inventory size

The 5 Florida counties nearest Monroe County in number of bridges, with their condition splits. Its 7% Poor share is the 4th-lowest of these 6. Its average build year of 1978 against a peer-group mean of 1978 is in line with the group.

Showing the 5 closest of 66 Florida counties eligible for comparison.

Bridge inventory size and condition shares for Monroe County and the 5 Florida counties closest to it in inventory size
County Bridges Poor
Flagler County 105 1.9%
Nassau County 104 2.9%
Monroe County (this page) 100 7%
Washington County 99 10.1%
Baker County 93 8.6%
Clay County 90 3.3%

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

Similar inventory size

Nearest county inventories outside FL (100 bridges here).

Similar average build year

Nearest mean year-built outside FL (1978 here).

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

All bridges (100)

US 1 (SR 5)

Fair

Over: CHANNEL #5

FIESTA-CRAIG KEY (MM 71), Monroe, FL

Built 1982 Load: 7.2 t ADT: 11,500

US 1 (SR 5)

Fair

Over: LONG KEY CHANNEL

LONG KEY (MM 63.2), Monroe, FL

Built 1981 Load: 10.1 t ADT: 13,200

116th Street

Fair

Over: Venice Waterway

200Ft. S of US 1 MM 52.9, Monroe, FL

Built 1967 Load: 10.8 t ADT: 593

US 1 (SR 5)

Fair

Over: CHANNEL #2

MATECUMBE KEY (MM 73.0), Monroe, FL

Built 1981 Load: 13.1 t ADT: 12,700

Watson Road

Fair

Over: Bogie Channel

3.5 Mi E of SR 5(MM 30.5), Monroe, FL

Built 1967 Load: 14.7 t ADT: 1,300

Valois Blvd.

Fair

Over: Canal

200Ft. E of CR-905, Monroe, FL

Built 1995 Load: 18.5 t ADT: 282

US 1 (SR 5)

Fair

Over: MOSER CHANNEL

MARATHON KEY (MM 40-46.6), Monroe, FL

Built 1982 Load: 19.6 t ADT: 11,300

FLEMING KEY ROAD

Fair

Over: GARRISON BIGHT

1.5 KM N OF US 1, Monroe, FL

Built 1965 Load: 20.5 t ADT: 250

112th Street

Fair

Over: Caloosa Channel

100Ft. S of US-1 MM 52.7, Monroe, FL

Built 1965 Load: 22.2 t ADT: 593

Card Sound Road

Fair

Over: I.C.W.W

11.0 Miles SE of US 1, Monroe, FL

Built 1969 Load: 25.6 t ADT: 3,157

Yellow Tail Road

Fair

Over: Un-Named Canal

40Ft. N of Aviation Blvd., Monroe, FL

Built 1983 Load: 25.9 t ADT: 261

US 1 (SR 5)

Fair

Over: NILES CHANNEL

SUMMERLAND KEY (MM 25.5), Monroe, FL

Built 1981 Load: 26.5 t ADT: 16,900

MAIN PARK ROAD

Fair

Over: BUTTONWOOD CANAL

37.33 MILES FROM PARK ENT, Monroe, FL

Built 1957 Load: 27.2 t ADT: 690

Duck Key Drive

Fair

Over: Duck Key Channel

0.5 Mile E of US1 MM 61.1, Monroe, FL

Built 1955 Load: 27.6 t ADT: 830

CR 905A

Fair

Over: Steam Boat Creek

1.6 Miles N of CR 905, Monroe, FL

Built 1968 Load: 27.6 t ADT: 3,182

Old State Road 4A

Fair

Over: Sugarloaf Creek

5 Mi. E & S of US-1 MM 17, Monroe, FL

Built 1968 Load: 28.7 t ADT: 617

Palm Avenue

Fair

Over: Garrison Bight

0.2 Mile W of US-1, Monroe, FL

Built 1965 Load: 29.3 t ADT: 15,026

Sadowski Cswy.

Fair

Over: Beamers Channel

0.2Mi. E of US-1 (MM53.5), Monroe, FL

Built 2006 Load: 29.4 t ADT: 7,027

Boca Chica(CR-941)

Fair

Over: Geiger Key Cut

2.8Mi S of SR-5 (MM 10.7), Monroe, FL

Built 1955 Load: 30.0 t ADT: 592

Bahama Road

Fair

Over: Dougs Canal

200Ft S/O US1 at MM 98.4, Monroe, FL

Built 1962 Load: 30.8 t ADT: 51

Caribbean Drive

Fair

Over: Summerland Key Cove

100Ft. E of US1 At MM24.5, Monroe, FL

Built 1960 Load: 31.8 t ADT: 781

Beach Road

Fair

Over: Calley Slough

US-1 MM 102, Monroe, FL

Built 1967 Load: 32.1 t ADT: 1,869

Fern Avenue

Fair

Over: Joes Canal

230Ft. North of Watson Bl, Monroe, FL

Built 1960 Load: 32.1 t ADT: 700

MAIN PARK ROAD

Fair

Over: TAYLOR SLOUGH

0.9 MILES FROM PARK ENTRA, Monroe, FL

Built 2000 Load: 32.7 t ADT: 943

MAIN PARK ROAD

Fair

Over: TAYLOR SLOUGH

1.1 MILES FROM PARK ENTRA, Monroe, FL

Built 2000 Load: 32.7 t ADT: 943

US 1 SB (900016)

Fair

Over: BIG SPANISH CHANNEL

BAHIA HONDA KEY (MM 36.0), Monroe, FL

Built 1972 Load: 33.3 t ADT: 6,850

US 1 NB (900045)

Fair

Over: BIG SPANISH CHANNEL

BAHIA HONDA KEY (MM 36.0), Monroe, FL

Built 1972 Load: 33.3 t ADT: 6,850

Duck Key Drive

Fair

Over: Toms Harbor Channel

50Ft. E of US-1 MM61, Monroe, FL

Built 1967 Load: 33.3 t ADT: 1,700

Park Entrance Road

Fair

Over: Little Crawl Key Channel

220Ft. South of US-1, Monroe, FL

Built 2010 Load: 33.7 t ADT: 50

25th Street

Fair

Over: Un-named Canal

0.2 Mile S of US-1 MM48.5, Monroe, FL

Built 1967 Load: 34.1 t ADT: 600

CR 905A Card Sound

Fair

Over: Saunders Creek

3.5 Miles N of CR 905, Monroe, FL

Built 1969 Load: 34.7 t ADT: 3,184

US 1 (SR 5)

Fair

Over: SHARK CHANNEL

SHARK KEY (MM 11.3), Monroe, FL

Built 1979 Load: 34.9 t ADT: 17,600

US 1 (SR 5)

Fair

Over: SALT RUN

KEY WEST (MM 2.3), Monroe, FL

Built 1992 Load: 34.9 t ADT: 38,500

US 1 (SR 5)

Fair

Over: LOWER SUGARLOAF CHANNEL

SUGARLOAF KEY (MM 15.5), Monroe, FL

Built 1981 Load: 35.4 t ADT: 17,600

US 1 SB (900074)

Fair

Over: BOCA CHICA CHANNEL

BOCA CHICA KEY (MM 6.0), Monroe, FL

Built 1973 Load: 35.9 t ADT: 13,500

US 1 (SR 5)

Fair

Over: SPANISH HARBOR CHANNEL

BIG PINE KEY (MM 33.5), Monroe, FL

Built 1982 Load: 36.1 t ADT: 13,700

US 1 NB (900127)

Fair

Over: TAVERNIER CREEK

TAVERNIER KEY (MM 90.8), Monroe, FL

Built 1978 Load: 36.3 t ADT: 15,000

US 1 (SR 5)

Fair

Over: TEATABLE RELIEF

MATECUMBE KEY (MM 79.4), Monroe, FL

Built 1979 Load: 37.6 t ADT: 15,800

US 1 (SR 5)

Fair

Over: BOW CHANNEL

N SUGARLOAF KEY (MM 20.2), Monroe, FL

Built 1982 Load: 37.6 t ADT: 16,900

US 1 (SR 5)

Fair

Over: SADDLE BUNCH #2

N OF BOCA CHICA (MM14.6), Monroe, FL

Built 1981 Load: 39.1 t ADT: 17,600

Copa D Oro Road

Fair

Over: Un-Named Canal

150Ft. S of Sombrero Blvd, Monroe, FL

Built 1983 Load: 39.3 t ADT: 243

US 1 (SR 5)

Fair

Over: HARRIS CHANNEL

SUGARLOAF KEY (MM 16.5), Monroe, FL

Built 1982 Load: 40.0 t ADT: 16,900

US 1 (SR 5)

Fair

Over: NORTH HARRIS CHANNEL

SUGARLOAF KEY (MM 17.7), Monroe, FL

Built 1981 Load: 40.0 t ADT: 16,900

US 1 (SR 5)

Fair

Over: MISSOURI LITTLE DUCK CH.

LITTLE DUCK KEY (MM 39.6), Monroe, FL

Built 1981 Load: 40.3 t ADT: 11,300

US-1 (SR-5)

Fair

Over: OHIO-BAHIA HONDA CHANL

BAHIA HONDA KEY (MM 38.5), Monroe, FL

Built 1981 Load: 40.3 t ADT: 11,300

US 1 (SR 5)

Fair

Over: TORCH CHANNEL

TORCH KEY (MM 28.0), Monroe, FL

Built 1982 Load: 40.6 t ADT: 18,000

Coco Plum Drive

Fair

Over: Bonefish Bay

0.3 mi. E of US-1 MM 54.1, Monroe, FL

Built 1977 Load: 41.2 t ADT: 618

US 1 (SR 5)

Fair

Over: TOMS HARBOR CUT

DUCK KEY (MM 61.4), Monroe, FL

Built 1980 Load: 41.5 t ADT: 12,700

US 1 (SR 5)

Fair

Over: TORCH RAMROD CHANNEL

TORCH RAMROD KEY(MM 27.7), Monroe, FL

Built 1982 Load: 42.5 t ADT: 18,300

US 1 (SR 5)

Fair

Over: INDIAN KEY CHANNEL

MATECUMBE KEY (MM 78.0), Monroe, FL

Built 1981 Load: 43.5 t ADT: 15,800
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.