County profile · official public datasets

St. Lawrence County, NY

312 public highway bridges tracked in the FHWA National Bridge Inventory: 59.9% rated Good, 33.3% Fair, 6.7% Poor.

312
Public bridges: 59.9%
Good condition: 6.7%
Poor condition

The verdict

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

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

Top 21%
lowest Poor share in state: 6.7%
Poor-condition share: 312
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.

St. Lawrence County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, St. Lawrence County ranks #13 of 62 New York counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 6.7%). St. Lawrence County, New York contains 312 public highway bridges. Roughly 59.9% are rated “Good,” 33.3% “Fair,” and 6.7% “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

312

Public highway bridges in St. Lawrence County

Good condition

59.9%

187 of 312 rated 7-9

Fair condition

33.3%

104 of 312 rated 5-6

Poor condition

6.7%

21 of 312 rated 4 or below

In-state Poor-share rank

#13 of 62

Among New York counties with 5+ bridges, lower share ranks better

Condition distribution

Share of 312 NBI-tracked bridges by lowest applicable component rating.

Good

59.9% (187)

Fair

33.3% (104)

Poor

6.7% (21)

St. Lawrence County's Poor-condition bridges carry 7,998 vehicle crossings a day

That is 1.9% of the county's reported daily bridge traffic on 6.8% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 381 crossings a day against 1,389 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 308 of 312 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

45.8% of St. Lawrence County's bridges have passed the 50-year mark

143 of the 312 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 59.9% 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 37.9% of the county's Poor-condition bridge traffic

RTE 812 over CAN.QUEENS HWY.2 ST.LAW, built 1960, carries 3,033 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 21-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 7,998 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

pre-1900

4
1900s

3
1910s

5
1920s

17
1930s

23
1940s

7
1950s

34
1960s

46
1970s

15
1980s

31
1990s

40
2000s

33
2010s

42
2020s

12

What this shows Construction peaked in the 1960s, when 46 of the county's bridges still in the inventory were built, which is 14.7% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year (1976) matches the New York average (1972).

How St. Lawrence County compares with New York's closest counties by inventory size

The 5 New York counties nearest St. Lawrence County in number of bridges, with their condition splits. Its 6.7% Poor share is the 3rd-lowest of these 6. Its average build year of 1976 against a peer-group mean of 1963 is 13 years newer.

Showing the 5 closest of 61 New York counties eligible for comparison.

Bridge inventory size and condition shares for St. Lawrence County and the 5 New York counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Albany County	343	29.7%	65%	5.2%	1975
Dutchess County	332	22.6%	60.8%	16.6%	1967
Nassau County	328	28.4%	70.4%	1.2%	1959
Jefferson County	316	41.5%	47.8%	10.8%	1971
St. Lawrence County (this page)	312	59.9%	33.3%	6.7%	1976
Bronx County	311	16.1%	75.6%	8.4%	1945

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 St. Lawrence 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 St. Lawrence County, both outside New York so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside NY (312 bridges here).

Saline County, NE · 312 bridges
Beckham County, OK · 312 bridges
Natchitoches County, LA · 313 bridges
Linn County, MO · 313 bridges

Similar average build year

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

Marion County, IN · avg 1976 · 958 bridges
Mohave County, AZ · avg 1976 · 641 bridges
Comanche County, OK · avg 1976 · 593 bridges
Prince George's County, MD · avg 1976 · 576 bridges

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

All 312 Good 187 Fair 104 Poor 21

All bridges (312)

Sort:

St. Lawrence County Bridge Snapshot

Condition distribution

St. Lawrence County's Poor-condition bridges carry 7,998 vehicle crossings a day

45.8% of St. Lawrence County's bridges have passed the 50-year mark

One structure carries 37.9% of the county's Poor-condition bridge traffic

How St. Lawrence County compares with New York'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 (312)

RTE 421

RIDGE-SPRING STRT

MAIN STREET

HEWITTVILLE ROAD

DRY BRIDGE ROAD

EDDY PYRITES ROAD

OLD DEKALB-CANTON

RIVER ROAD

ROSE ROAD

GARRISON ROAD

COUNTY ROAD 9

MCINTYRE ROAD

JONES ROAD

COUSINTOWN ROAD

COUNTY ROAD 38

COUNTY ROAD 34

CAMPBELL ROAD

WELCH ROAD

HOADLEY ROAD

COUNTY ROAD 27

COUNTY ROAD 22

DEAN ROAD

TOOLEY POND ROAD

SPICER ROAD

COUNTY ROAD 35

RTE 37

RTE 37

COUNTY ROAD 28A

COUNTY ROAD 21

RTE 11C

RTE 37

MILL ROAD

COUNTY ROAD 54

RTE 11B

RTE 812

RTE 56

LAFAYETTE SPRG ST

EDWRDS-HER-CAN RD

COUNTY ROAD 27

MCINTYRE ROAD

CR 31

CEMETERY ROAD

NICHOLS ROAD

CONN. NY 37 &CANAD

BARNHART ISLAND RD

RTE 37C

EDDY PYRITES ROAD

SPRAGUEVILLE ROAD

CO RD 44

RTE 37

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