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

Good-condition bridges (200)

MD 200 (ICC) EB

Good

Over: Bonifant Road & NW Branc

2.07 Mi. West of MD650, Montgomery, MD

Built 2010 Load: 51.7 t ADT: 32,786

IS 270 RAMP A 1

Good

Over: IS 270 RAMP B

AT I-270/I-270 SPUR SPLIT, Montgomery, MD

Built 1995 Load: 52.2 t ADT: 10,196

US 29 SBR

Good

Over: MD 198

1.53 M S OF HOWARD CO LNE, Montgomery, MD

Built 2002 Load: 52.6 t ADT: 49,203

NORBECK RD (MD28)

Good

Over: MD 200 (ICC)

4.1 MI WEST OF MD 65, Montgomery, MD

Built 2010 Load: 52.6 t ADT: 18,475

IS 370 RAMP F

Good

Over: IS 370

0.16 MI E OF IS 270, Montgomery, MD

Built 1989 Load: 53.1 t ADT: 14,302

IS-370 EBR

Good

Over: IS-370 RP1 MD200 RP7

5.67 MI WEST OF MD 97, Montgomery, MD

Built 2010 Load: 53.5 t ADT: 39,531

NEEDWOOD ROAD

Good

Over: MD 200 (ICC)

2.88 MI W OF MD 97, Montgomery, MD

Built 2010 Load: 53.5 t ADT: 760

MD 97

Good

Over: Meadow Branch

2 MI. N OF OLNEY, Montgomery, MD

Built 2021 Load: 53.8 t ADT: 10,400

NOTLEY ROAD

Good

Over: MD 200 (ICC)

0.71 MI WEST OF MD 650, Montgomery, MD

Built 2010 Load: 54.0 t ADT: 4,997

INWOOD AVENUE

Good

Over: TRIBUTARY TO SLIGO CREEK

AT FOLK STREET, Montgomery, MD

Built 1956 Load: 54.4 t ADT: 2,972

JEB STUART TRAIL

Good

Over: TRIB TO LITTLE MONOCACY

0.18 MI WEST OF MD RTE 28, Montgomery, MD

Built 2010 Load: 54.9 t ADT: 20

MD 28

Good

Over: SENECA CREEK

0.2 MILE EAST OF MD 107, Montgomery, MD

Built 2000 Load: 55.8 t ADT: 11,520

CLARKSBURG ROAD

Good

Over: LITTLE BENNETT CREEK

1.9 MI N OF MD 355, Montgomery, MD

Built 1998 Load: 56.2 t ADT: 2,934

MD 200 (ICC) EB

Good

Over: Ramp NW

0.6 mi W of Briggs Chaney, Montgomery, MD

Built 2011 Load: 56.2 t ADT: 22,682

INDUSTRIAL DRIVE

Good

Over: IS 370

0.51 MI E OF IS 270, Montgomery, MD

Built 1989 Load: 56.7 t ADT: 999

BRIGGS CHANEY ROAD

Good

Over: US 29

AT US 29, Montgomery, MD

Built 2007 Load: 57.1 t ADT: 11,212

WHITES FERRY ROAD

Good

Over: BROAD RUN TRIBUTARY

2 MI W OF JCT SR 109, Montgomery, MD

Built 1998 Load: 57.1 t ADT: 1,999

DAHLGREN ROAD

Good

Over: PAINT BRANCH

GSA at White Oak MD. I-, Montgomery, MD

Built 2009 Load: 57.1 t ADT: 110

BURNING TREE ROAD

Good

Over: BOOZE CREEK

0.5 MILES SOUTH OF MD 191, Montgomery, MD

Built 2008 Load: 57.6 t ADT: 1,938

Ramp WS & WN

Good

Over: Ramp NW

0.5 mi S Briggs Chaney Rd, Montgomery, MD

Built 2011 Load: 57.6 t ADT: 2,706

CLARKSBURG ROAD

Good

Over: LITTLE BENNETT CREEK TRI

2.8 MILES NORTH OF MD 355, Montgomery, MD

Built 1988 Load: 58.0 t ADT: 2,969

MD 200 (ICC) EB

Good

Over: Good Hope Tributary

0.48 Mi East of MD650, Montgomery, MD

Built 2010 Load: 58.5 t ADT: 31,755

Ramp ES

Good

Over: Ramp SE

0.12 mi W of 29/200 I/C, Montgomery, MD

Built 2011 Load: 58.5 t ADT: 2,449

MUNCASTER MILL RD

Good

Over: MD 200 (ICC)

2.33 MI W OF MD 97, Montgomery, MD

Built 2010 Load: 59.0 t ADT: 19,690

MD 410

Good

Over: GEORGETOWN BRANCH TRAIL

0.52 MILE EAST OF MD 355, Montgomery, MD

Built 1997 Load: 59.4 t ADT: 26,061

LINDEN LANE

Good

Over: CSXT RAILROAD

0.5 MI W OF SEMINARY ROAD, Montgomery, MD

Built 1996 Load: 59.9 t ADT: 4,090

PENNYFIELD LOCK RO

Good

Over: UNNAMED TRIBUTARY

0.8 MI S OF RIVER ROAD, Montgomery, MD

Built 2017 Load: 59.9 t ADT: 529

LITTLE SENECA PKWY

Good

Over: LITTLE SENECA CREEK

0.1 MI. E. OF MD 355, Montgomery, MD

Built 2014 Load: 59.9 t ADT: 10,875

MD 200 Ramp ES

Good

Over: MD 200 (ICC) Ramp SB

0.10 Mi. West of US 29, Montgomery, MD

Built 2010 Load: 59.9 t ADT: 2,449

MD 200 (ICC) WB

Good

Over: Good Hope Tributary

0.45 Mi East of MD650, Montgomery, MD

Built 2010 Load: 60.3 t ADT: 32,064

MD 187B (ROCKLEDGE

Good

Over: 1S 270

0.29 MILE NORTH OF MD 187, Montgomery, MD

Built 2002 Load: 60.8 t ADT: 19,205

BROOKSIDE VISITORS

Good

Over: NORTHWEST BRANCH TRIBUTA

ENT. FROM GLENALLEN AVE., Montgomery, MD

Built 1999 Load: 60.8 t ADT: 55

IS 370

Good

Over: IS 370 RAMP M

0.21 MILE EAST OF MD 355, Montgomery, MD

Built 1988 Load: 61.2 t ADT: 81,998

PEACH TREE ROAD

Good

Over: CSXT RAILROAD

1 MI S OF BARNESVILLE RD, Montgomery, MD

Built 2000 Load: 61.2 t ADT: 400

US 29

Good

Over: IS 495

0.34 MILE SOUTH OF MD 193, Montgomery, MD

Built 1959 Load: 62.1 t ADT: 56,842

FATHER HURLEY BOUL

Good

Over: I-270

0.5MI E. OF CRYSTAL RK DR, Montgomery, MD

Built 1995 Load: 62.1 t ADT: 14,319

FATHER HURLEY BOUL

Good

Over: I-270

.5 MI E. OF CRYSTAL RK DR, Montgomery, MD

Built 1995 Load: 62.1 t ADT: 13,713

MUDDY BRANCH RD EB

Good

Over: IS 270 & NB C-D ROAD

0.73 MI E OF MD 117, Montgomery, MD

Built 1989 Load: 62.6 t ADT: 14,642

CLARKSBURG ROAD

Good

Over: BENNETT CREEK

2.2 MI SW OF JCT SR 80, Montgomery, MD

Built 2011 Load: 63.0 t ADT: 4,123

IS 270 SB

Good

Over: MD 109 LITTLE BENNETT C

0.22 MI S OF FREDERICK CO, Montgomery, MD

Built 1950 Load: 63.5 t ADT: 87,230

I-370 RAMP L(7)

Good

Over: I-370 RAMP M(3)

.23 MI E OF MD 355, Montgomery, MD

Built 2010 Load: 63.5 t ADT: 3,953

DEMOCRACY BLVD

Good

Over: IS 270Y

@ IS 270Y, Montgomery, MD

Built 2003 Load: 64.4 t ADT: 25,601

FIRST STREET

Good

Over: ROCK CREEK TRIBUTARY

0.07 MILE WEST OF MD28, Montgomery, MD

Built 2017 Load: 64.8 t ADT: 3,496

IS 270 NB

Good

Over: MD 109 LITTLE BENNETT C

0.22 MI S OF FREDERICK CO, Montgomery, MD

Built 1950 Load: 65.3 t ADT: 87,230

WHITES FERRY ROAD

Good

Over: BROAD RUN TRIBUTARY

1 MI W OF ELGIN ROAD, Montgomery, MD

Built 2014 Load: 65.3 t ADT: 1,836

NORBECK ROAD

Good

Over: NURSERY RUN

0.98 MILES EAST OF MD 182, Montgomery, MD

Built 2002 Load: 65.3 t ADT: 18,960

Ramp WN to US29 NB

Good

Over: Ramp NB to Briggs Chaney

0.8 Mi S Briggs Chaney Rd, Montgomery, MD

Built 2011 Load: 65.3 t ADT: 309

WATKINS MILL ROAD

Good

Over: GREAT SENECA CREEK

.6 MI SE OF BLUNT ROAD, Montgomery, MD

Built 1990 Load: 65.7 t ADT: 12,760

MUDDY BRANCH RD WB

Good

Over: IS 270 & NB C-D ROAD

0.85 MI N OF IS 370, Montgomery, MD

Built 1989 Load: 65.8 t ADT: 14,642

IS 370

Good

Over: OAKMONT AVENUE

0.37 MILE EAST OF MD 355, Montgomery, MD

Built 1989 Load: 66.2 t ADT: 78,741

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

Related

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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.