County profile · official public datasets

Multnomah County, OR

473 public highway bridges tracked in the FHWA National Bridge Inventory: 11.8% rated Good, 85.2% Fair, 3% Poor.

473
Public bridges: 11.8%
Good condition: 3%
Poor condition

The verdict

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

Multnomah County pairs a better-than-median Poor-condition share among rated counties in the state with an older average build year than the state inventory.

Top 42%
lowest Poor share in state: 3%
Poor-condition share: 473
public highway bridges: 1967
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.

Multnomah County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Multnomah County ranks #15 of 36 Oregon counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 3%). Multnomah County, Oregon contains 473 public highway bridges. Roughly 11.8% are rated “Good,” 85.2% “Fair,” and 3% “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

473

Public highway bridges in Multnomah County

Good condition

11.8%

56 of 473 rated 7-9

Fair condition

85.2%

403 of 473 rated 5-6

Poor condition

14 of 473 rated 4 or below

In-state Poor-share rank

#15 of 36

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

Condition distribution

Share of 473 NBI-tracked bridges by lowest applicable component rating.

Good

11.8% (56)

Fair

85.2% (403)

Poor

3% (14)

Multnomah County's Poor-condition bridges carry 216,393 vehicle crossings a day

That is 1.4% of the county's reported daily bridge traffic on 3% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 15,457 crossings a day against 17,766 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 473 of 473 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

61.5% of Multnomah County's bridges have passed the 50-year mark

291 of the 473 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 11.8% 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 26.6% of the county's Poor-condition bridge traffic

Hwy 001 NB over Columbia River, built 1916, carries 57,550 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 14-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 216,393 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1900s

9
1910s

30
1920s

17
1930s

25
1940s

19
1950s

50
1960s

107
1970s

63
1980s

61
1990s

44
2000s

28
2010s

17
2020s

3

What this shows Construction peaked in the 1960s, when 107 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 55 to 64 years old in the 2024 inventory. Its average build year is 1967, 8 years older than the Oregon average of 1975.

How Multnomah County compares with Oregon's closest counties by inventory size

The 5 Oregon counties nearest Multnomah County in number of bridges, with their condition splits. Its 3% Poor share is the 4th-lowest of these 6. Its average build year of 1967 against a peer-group mean of 1975 is 8 years older.

Showing the 5 closest of 35 Oregon counties eligible for comparison.

Bridge inventory size and condition shares for Multnomah County and the 5 Oregon counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Linn County	566	20.8%	61.5%	17.7%	1971
Multnomah County (this page)	473	11.8%	85.2%	3%	1967
Jackson County	401	34.2%	64.3%	1.5%	1976
Marion County	373	21.2%	74.5%	4.3%	1971
Clackamas County	367	31.1%	66.5%	2.5%	1975
Washington County	326	35.6%	62%	2.5%	1983

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

Similar inventory size

Nearest county inventories outside OR (473 bridges here).

Onondaga County, NY · 472 bridges
Orange County, NY · 472 bridges
Pierce County, WA · 472 bridges
Jasper County, MO · 471 bridges

Similar average build year

Nearest mean year-built outside OR (1967 here).

Los Angeles County, CA · avg 1967 · 3,547 bridges
Allegheny County, PA · avg 1967 · 1,294 bridges
Sonoma County, CA · avg 1967 · 609 bridges
Merced County, CA · avg 1967 · 528 bridges

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

All 473 Good 56 Fair 403 Poor 14

Fair-condition bridges (403)

Sort:

Multnomah County Bridge Snapshot

Condition distribution

Multnomah County's Poor-condition bridges carry 216,393 vehicle crossings a day

61.5% of Multnomah County's bridges have passed the 50-year mark

One structure carries 26.6% of the county's Poor-condition bridge traffic

How Multnomah County compares with Oregon's closest counties by inventory size

Nationwide counties with similar inventory size or average build year

Similar inventory size

Similar average build year

Fair-condition bridges (403)

Milwaukie Ave

Broadway St.

HY 1 NB TO HY 2

SW OSAGE ST

OR 99W SB

WB CON TO HWY 1 SB

I-5 (Hwy 1)

Hwy 100

Viaduct

Hwy 091

Skidmore St

SE 159TH DRIVE

SW HIGHLAND DRIVE

I-5 (HWY 001) SB

OR 213 (NE 82nd)

HAWTHORNE BRIDGE

ROAD

I-405 (HWY 061) CO

NW COUCH ST CO

STEEL BRIDGE RAMP

SW CAPITOL HIGHWAY

SE 45TH AVE

I-5 (HWY 001) CON

FREMONT ON RAMP

Hwy 001 Conn 2

CONN TO HWY 61 NB

STARK STREET

Hwy 064 (I-205 Co)

Hwy 064 (I-205) Co

COLUMBIA BLVD

I-84 (HWY 002) WB

CONN HWY 26 HWY 91

NE 39TH AVE

NE Mt. Hood Ave.

Glisan St

SW 5TH AVE

Hwy 002

I-84 (HWY 002) CON

I-84 (HWY 002) CON

E FREMONT APPROACH

SE 92ND AVE

Hwy 002 WB

SW 19th Ave

Hwy 068

NE 47TH AVE

Terwilliger Blvd.

SE HOLGATE BLVD

Hwy 064 NB

N BROADWAY ST

OFF RAMP

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