County profile · official public datasets

Montgomery County, MD

515 public highway bridges tracked in the FHWA National Bridge Inventory: 38.8% rated Good, 56.3% Fair, 4.9% Poor.

515
Public bridges
38.8%
Good condition
4.9%
Poor condition

The verdict

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

Montgomery County pairs a higher-than-median Poor-condition share among rated counties in the state with a newer average build year than the state inventory.

14th
of 24 on Poor share
4.9%
Poor-condition share
515
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.

Montgomery County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Montgomery County ranks #14 of 24 Maryland counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 4.9%). Montgomery County, Maryland contains 515 public highway bridges. Roughly 38.8% are rated “Good,” 56.3% “Fair,” and 4.9% “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

515

Public highway bridges in Montgomery County

Good condition

38.8%

200 of 515 rated 7-9

Fair condition

56.3%

290 of 515 rated 5-6

Poor condition

4.9%

25 of 515 rated 4 or below

In-state Poor-share rank

#14 of 24

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

Condition distribution

Share of 515 NBI-tracked bridges by lowest applicable component rating.

Good
38.8% (200)
Fair
56.3% (290)
Poor
4.9% (25)

Montgomery County's Poor-condition bridges carry 242,194 vehicle crossings a day

That is 1.7% of the county's reported daily bridge traffic on 4.9% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 9,688 crossings a day against 21,166 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 513 of 515 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

44.9% of Montgomery County's bridges have passed the 50-year mark

231 of the 515 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 38.8% 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 16.5% of the county's Poor-condition bridge traffic

CLARA BARTON PARKW over CLARA BARTON PARKWAY (SB, built 1959, carries 40,057 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 25-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 242,194 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Montgomery County's bridges were built

515 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1960s, when 84 of the county's bridges still in the inventory were built, which is 16.3% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year is 1978, 6 years newer than the Maryland average of 1972.

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

How Montgomery County compares with Maryland's closest counties by inventory size

The 5 Maryland counties nearest Montgomery County in number of bridges, with their condition splits. Its 4.9% Poor share is the 4th-lowest of these 6. Its average build year of 1978 against a peer-group mean of 1974 is in line with the group.

Showing the 5 closest of 23 Maryland counties eligible for comparison.

Bridge inventory size and condition shares for Montgomery County and the 5 Maryland counties closest to it in inventory size
County Bridges Poor
Prince George's County 576 3.1%
Montgomery County (this page) 515 4.9%
Frederick County 486 2.7%
Anne Arundel County 389 1.5%
Baltimore city County 374 8.6%
Howard County 309 5.8%

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

Similar inventory size

Nearest county inventories outside MD (515 bridges here).

Similar average build year

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

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

All 515 Good 200 Fair 290 Poor 25

Fair-condition bridges (290)

EAST RANDOLPH ROAD

Fair

Over: PAINT BRANCH

0.5 MI W OLD COLUMBIA PK, Montgomery, MD

Built 1963 Load: 61.7 t ADT: 34,092

TACKBROOKE DRIVE

Fair

Over: ROCK CREEK NORTH BRANCH

N OF BOWIE MILL ROAD, Montgomery, MD

Built 2002 Load: 62.1 t ADT: 67

WEST OLD BALTIMORE

Fair

Over: LITTLE SENECA CREEK

1.0 MILES WEST OF MD 355, Montgomery, MD

Built 1934 Load: 62.6 t ADT: 1,069

COMUS ROAD

Fair

Over: IS 270

1.3 MI N OF MD 121, Montgomery, MD

Built 1952 Load: 63.5 t ADT: 2,540

MD 109

Fair

Over: LITTLE BENNETT CREEK

UNDER IS 270 OVERPASS, Montgomery, MD

Built 1951 Load: 63.5 t ADT: 7,232

GOSHEN ROAD

Fair

Over: WHETSTONE RUN TRIBUTARY

.25 MI N OF MIDCOUNTY HWY, Montgomery, MD

Built 1930 Load: 63.5 t ADT: 26,801

IS 495 & RAMP K(4)

Fair

Over: IS 495X & C J CR

0.49 MILE WEST OF MD 190, Montgomery, MD

Built 1962 Load: 63.9 t ADT: 214,005

WILDCAT ROAD

Fair

Over: WILDCAT BRANCH

2.4 MI SW OF MD 124, Montgomery, MD

Built 1935 Load: 63.9 t ADT: 431

LITTLE FALLS PARKW

Fair

Over: WILLET BRANCH

0.1 MI S OF HILLANDALE RD, Montgomery, MD

Built 1958 Load: 64.4 t ADT: 17,373

IS 495 RAMP E(10)

Fair

Over: CABIN JOHN CREEK

0.12 MI W OF IS 495X, Montgomery, MD

Built 1964 Load: 65.3 t ADT: 11,731

WARING STATION ROA

Fair

Over: CSXT RAILROAD

0.5 MI NORTH OF MD 117, Montgomery, MD

Built 1986 Load: 65.3 t ADT: 6,897

WHITES FERRY ROAD

Fair

Over: BROAD RUN

3 MILES WEST OF MD 109, Montgomery, MD

Built 1931 Load: 65.3 t ADT: 1,988

MD 190

Fair

Over: MUDDY BRANCH

0.98 M E OF PETTIT WAY, Montgomery, MD

Built 1954 Load: 66.2 t ADT: 3,592

RANDOLPH ROAD (WB)

Fair

Over: ROCK CREEK

0.6 MILES WEST OF MD 586, Montgomery, MD

Built 1951 Load: 66.2 t ADT: 23,434

MD 117

Fair

Over: BUCKLODGE BRANCH

3.12 MILES NORTH OF MD 28, Montgomery, MD

Built 1932 Load: 67.1 t ADT: 5,572

MD 118

Fair

Over: GREAT SENECA CREEK

1.3 MILES NORTH OF MD 28, Montgomery, MD

Built 1931 Load: 67.1 t ADT: 6,121

NICHOLSON LANE

Fair

Over: CSXT RAILROAD

0.5 MILES EAST OF MD 355, Montgomery, MD

Built 2008 Load: 67.1 t ADT: 38,971

DENNIS AVENUE

Fair

Over: SLIGO CREEK

0.7 MI E OF JCT SR 97, Montgomery, MD

Built 1999 Load: 67.1 t ADT: 10,971

BEACH DRIVE

Fair

Over: ROCK CREEK

0.15 MI N OF JCT SR 547, Montgomery, MD

Built 1966 Load: 67.1 t ADT: 8,663

TUCKERMAN LANE

Fair

Over: CABIN JOHN CREEK

1 MI E OF SEVEN LOCKS RD, Montgomery, MD

Built 1966 Load: 68.0 t ADT: 24,539

IS 495 OL

Fair

Over: IS 270Y

0.26 MILE EAST OF MD 191, Montgomery, MD

Built 1996 Load: 69.8 t ADT: 115,850

SEVEN LOCKS ROAD

Fair

Over: CABIN JOHN CREEK

.1 MI S OF DEMOCRACY BLVD, Montgomery, MD

Built 1960 Load: 71.2 t ADT: 30,260

MIDDLEBRIDGE DRIVE

Fair

Over: BEL PRE CREEK

0.1 MI EAST OF MD-182, Montgomery, MD

Built 1983 Load: 71.2 t ADT: 315

MORNINGWOOD DRIVE

Fair

Over: WILLIAMSBURG RUN TRIB

0.90 MI. W. OF MD 108, Montgomery, MD

Built 1970 Load: 72.6 t ADT: 5,113

IS 270

Fair

Over: TUCKERMAN LANE

0.08 MILE N OF IS 270Y, Montgomery, MD

Built 1958 Load: 73.0 t ADT: 265,320

GOSHEN ROAD

Fair

Over: WHETSTONE RUN

0.1 MI S MID-COUNTY HWY, Montgomery, MD

Built 1986 Load: 73.0 t ADT: 20,972

NELSON STREET

Fair

Over: WATTS BRANCH

0.5 MILES NORTH OF MD 28, Montgomery, MD

Built 1955 Load: 73.0 t ADT: 13,576

MD 586

Fair

Over: ROCK CREEK

1.68 MILES EAST OF MD 28, Montgomery, MD

Built 1954 Load: 73.5 t ADT: 56,222

IS 270 RAMP A(6)

Fair

Over: IS 495 OL

1.19 MILE SOUTH OF MD 187, Montgomery, MD

Built 1990 Load: 73.5 t ADT: 11,255

PRESERVE PARKWAY

Fair

Over: CABIN JOHN CREEK

0.2 MI E OF TOWER OAKS BL, Montgomery, MD

Built 2006 Load: 73.9 t ADT: 2,450

BEACH DRIVE

Fair

Over: TRIB TO ROCK CREEK

1.1 MI SOUTH OF MD 547, Montgomery, MD

Built 1968 Load: 75.7 t ADT: 6,263

SHADY GROVE RD WB

Fair

Over: CSXT RAILROAD

0.5 MI EAST OF MD 355, Montgomery, MD

Built 1976 Load: 76.6 t ADT: 35,374

IS 370 EB

Fair

Over: IS 370 RAMP B

0.07 MILE WEST OF IS 270, Montgomery, MD

Built 1990 Load: 77.1 t ADT: 78,741

MD 117

Fair

Over: GUNNERS BRANCH

1.21 MILES EAST OF MD 118, Montgomery, MD

Built 1951 Load: 78.9 t ADT: 18,752

BIG WOODS ROAD

Fair

Over: LITTLE MONOCACY RIVER

0.6 MI S OF JCT SR 28, Montgomery, MD

Built 1919 Load: 81.2 t ADT: 345

BEL PRE ROAD

Fair

Over: BEL PRE CREEK

0.5 MILES WEST OF MD 182, Montgomery, MD

Built 1955 Load: 83.0 t ADT: 31,186

BRIGHTON DAM ROAD

Fair

Over: HAWLINGS RIVER

0.9 MI W OF JCT SR MD 650, Montgomery, MD

Built 1920 Load: 83.0 t ADT: 2,990

DEMOCRACY BLVD

Fair

Over: BUCK BRANCH

2 MI E OF JCT SR MD 189, Montgomery, MD

Built 1988 Load: 83.0 t ADT: 16,780

SKYLARK ROAD

Fair

Over: LITTLE SENECA CREEK

0.7 MI WEST OF MD 27, Montgomery, MD

Built 2006 Load: 84.4 t ADT: 5,507

HUNTMASTER ROAD

Fair

Over: GOSHEN BRANCH

0.2 MI NORTH OF BRINK RD, Montgomery, MD

Built 1920 Load: 85.4 t ADT: 480

MD 355

Fair

Over: CAPITAL CRESCENT TRAIL

0.08 MILE SOUTH OF MD 410, Montgomery, MD

Built 1988 Load: 85.7 t ADT: 28,620

GLEN ROAD

Fair

Over: WATTS BRANCH

1.5 MI W OF JCT SR 189, Montgomery, MD

Built 1930 Load: 85.7 t ADT: 8,250

GRANITE ROCK ROAD

Fair

Over: TRIBUTARY TO LITTLE SENE

1 MI NORTHEAST OF MD 355, Montgomery, MD

Built 2007 Load: 96.9 t ADT: 412

MD 108

Fair

Over: PATUXENT RIVER

ON HOWARD CO LINE, Montgomery, MD

Built 1928 Load: 99.9 t ADT: 12,871

IS 270

Fair

Over: LITTLE SENECA CREEK

1.85 south of MD 121, Montgomery, MD

Built 1954 Load: 99.9 t ADT: 98,097

IS 270

Fair

Over: OLD FARM CREEK

0.13 MILE N OF IS 270Y, Montgomery, MD

Built 1958 Load: 99.9 t ADT: 265,320

MD 117

Fair

Over: LITTLE SENECA CREEK

1.03 MILES EAST OF MD 121, Montgomery, MD

Built 1953 Load: 99.9 t ADT: 7,457

MD 190

Fair

Over: WATTS BRANCH

3.42 MILES WEST OF MD 189, Montgomery, MD

Built 1949 Load: 99.9 t ADT: 15,240

IS 495

Fair

Over: SLIGO CREEK

0.55 MILE EAST OF MD 97, Montgomery, MD

Built 1960 Load: 99.9 t ADT: 232,010

IS 495

Fair

Over: BR OF ROCK CREEK

0.6 MILE EAST OF MD 355, Montgomery, MD

Built 1958 Load: 99.9 t ADT: 238,050

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.