Boulder County, CO

311 public highway bridges

Boulder County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Boulder County, Colorado contains 311 public highway bridges. Roughly 33.4% are rated “Good,” 60.5% “Fair,” and 2.3% “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.

311
Total Bridges
33.4%
Good
60.5%
Fair
2.3%
Poor Condition

Condition Distribution

Good
33.4% (104)
Fair
60.5% (188)
Poor
2.3% (7)

All Bridges (311)

NFSR 112.0

Good

Over: SOUTH ST VRAIN CREEK

W. SIDE OF BRAINARD LAKE, Boulder, CO

Built 2011 ADT: 200

S. Pratt Parkway

Good

Over: St Vrain Creek

250 Ft S of Boston Ave, Boulder, CO

Built 2019 Load: 21.1 t ADT: 12,909

US 287 ML

Good

Over: COAL CREEK

IN BOULDER COUNTY, Boulder, CO

Built 1996 Load: 23.1 t ADT: 32,000

SH 7 ML

Good

Over: COAL CREEK

2.3 MI E OF JCT US 287, Boulder, CO

Built 1990 Load: 23.7 t ADT: 17,000

Second Avenue

Good

Over: St. Vrain Creek

0.15 Mi S of Hwy 36, Boulder, CO

Built 2021 Load: 23.7 t ADT: 946

US 287 ML

Good

Over: ST VRAIN CREEK

IN LONGMONT, Boulder, CO

Built 2016 Load: 25.9 t ADT: 24,000

N 63rd St (CR39)

Good

Over: Lefthand Creek

0.4 Mi N of Niwot Rd, Boulder, CO

Built 2011 Load: 26.9 t ADT: 2,610

Mountain Dr.

Good

Over: Clover Basin Ditch

200 ft S. of Four Leaf Dr, Boulder, CO

Built 2018 Load: 29.2 t ADT: 1,399

County Road 1

Good

Over: ST VRAIN CREEK

.5 mi south of SH119, Boulder, CO

Built 2014 Load: 29.5 t ADT: 9,344

30th Street

Good

Over: Boulder, Lefthand Ditch

400 Ft So of Pearl St, Boulder, CO

Built 2011 Load: 29.6 t ADT: 20,225

Airport Road

Good

Over: St. Vrain River

600 Ft. S of 9th Ave., Boulder, CO

Built 2006 Load: 30.9 t ADT: 13,131

Co Rd 3 / 119th S

Good

Over: Dry Creek No 2

0.9 Mi S of SH119, Boulder, CO

Built 2013 Load: 31.4 t ADT: 2,541

US 287 ML

Good

Over: DRAW

0.9 MI S OF JCT SH 52, Boulder, CO

Built 1990 Load: 32.3 t ADT: 23,000

Broadway

Good

Over: Four Mile Creek/Bike Pth

At Rosewood Avenue, Boulder, CO

Built 1994 Load: 32.4 t ADT: 11,874

Lefthand Canyon Dr

Good

Over: Lefthand Creek

0.75 Mi W of Lee Hill Dr, Boulder, CO

Built 2019 Load: 32.7 t ADT: 1,078

Monarch Road

Good

Over: Dry Creek

800 ft S of N 79th St, Boulder, CO

Built 2019 Load: 32.7 t ADT: 349

Co Rd 39 (65th St)

Good

Over: LYKINS GULCH

0.8 Mi N of Nelson Rd, Boulder, CO

Built 2012 Load: 32.7 t ADT: 741

Fairways Drive

Good

Over: Local Drainage

.4 Mi S of Neva Rd, Boulder, CO

Built 2005 Load: 32.7 t ADT: 622

Golf Club Drive

Good

Over: Local Drainage

0.1 Mi So of Hogan Ct, Boulder, CO

Built 2005 Load: 32.7 t ADT: 644

Golf Club Drive

Good

Over: Local Drainage

0.4 Mi So of Hogan Ct, Boulder, CO

Built 2005 Load: 32.7 t ADT: 318

Wildwood Road

Good

Over: Bear Canyon Creek

150 Ft W of Bear Mtn. Rd, Boulder, CO

Built 1970 Load: 32.7 t ADT: 242

48th CT

Good

Over: S. Goose Creek

30 Ft N of Pearl Parkway, Boulder, CO

Built 1986 Load: 32.7 t ADT: 641

Mohawk Drive

Good

Over: Bear Crk and Bike Path

0.25 Mi No of Baseline Rd, Boulder, CO

Built 1996 Load: 32.7 t ADT: 1,707

Aurora Avenue

Good

Over: Gregory Creek

15 Ft. W of 6th Street, Boulder, CO

Built 1980 Load: 32.7 t ADT: 226

27th Street

Good

Over: Goose Creek

50 ft N of Mapleton Ave, Boulder, CO

Built 2001 Load: 32.7 t ADT: 201

34th Street

Good

Over: Wonderland Creek

40 ft S. of Iris Ave, Boulder, CO

Built 2018 Load: 32.7 t ADT: 1,200

Gilpin Drive

Good

Over: Bear Canyon Creek

350 ft S of Evans Dr, Boulder, CO

Built 1997 Load: 32.7 t ADT: 281

Valmont Road

Good

Over: Elmers Twomile Creek

400 ft W of 28th, Boulder, CO

Built 2010 Load: 32.7 t ADT: 10,720

48th Street

Good

Over: Goose Creek

Just N. of Pearl St, Boulder, CO

Built 1980 Load: 32.7 t ADT: 664

Harvard Street

Good

Over: Oligarchy Ditch

50 Ft So. of N. Shore Dr., Boulder, CO

Built 1998 Load: 32.7 t ADT: 2,509

Sunset Street

Good

Over: Saint Vrain Creek

0.1 S Boston Ave, Boulder, CO

Built 2016 Load: 32.7 t ADT: 7,282

96th Street

Good

Over: BNSF RR

250 Ft. N of CR 19, Boulder, CO

Built 2006 Load: 32.7 t ADT: 15,821

Kalmia Avenue

Good

Over: Dry Creek

350 Ft East of US 36, Boulder, CO

Built 2017 Load: 33.0 t ADT: 2,621

US 36 ML

Good

Over: NORTH ST VRAIN CREEK

IN LYONS, Boulder, CO

Built 2007 Load: 33.0 t ADT: 9,000

Niwot Road CR34

Good

Over: Boulder Feeder Ditch

100 Ft. E of N. 55th St, Boulder, CO

Built 2010 Load: 33.2 t ADT: 2,084

Grandview Meadow D

Good

Over: Dry Creek

0.4 Mi So of Nelson Rd, Boulder, CO

Built 2004 Load: 33.2 t ADT: 3,692

N. 95th St (CR19)

Good

Over: Left Hand Creek

.4 Mi S of SH 119, Boulder, CO

Built 2009 Load: 33.6 t ADT: 11,067

N. 95th St (CR10)

Good

Over: Highland Ditch

0.5 Mi N of Woodland, Boulder, CO

Built 1989 Load: 33.7 t ADT: 1,968

US 36 ML

Good

Over: Ped Underpath / Creek

28TH ST/WINDING TRAIL DR., Boulder, CO

Built 2015 Load: 33.7 t ADT: 16,000

Marshall Rd(Cr 51)

Good

Over: South Boulder Creek

0.5 Mi N of St Hwy 170, Boulder, CO

Built 1988 Load: 33.8 t ADT: 318

83rd St (CO Rd 23)

Good

Over: Little Thompson River

1.8 Mi N of Woodland, Boulder, CO

Built 2017 Load: 34.3 t ADT: 2,443

Marshall Road

Good

Over: Coal Creek

0.07 Mi N of Creek View, Boulder, CO

Built 2022 Load: 34.3 t ADT: 1,867

US 36 ML

Good

Over: RAMP B & BIKEPATH

1.5 MI E. OF SUPERIOR, Boulder, CO

Built 2001 Load: 34.7 t ADT: 68,000

County Road 94

Good

Over: Lefthand Creek

0.1 Mi N of Olde Stage Rd, Boulder, CO

Built 2019 Load: 35.3 t ADT: 1,441

US 36 ML

Good

Over: LEFT HAND CREEK

6.2 MI SO OF JCT SH 66, Boulder, CO

Built 2019 Load: 35.6 t ADT: 13,000

McConnell Dr.

Good

Over: Saint Vrain Creek Ovrflw

300 ft S of US36 / SH66, Boulder, CO

Built 2018 Load: 35.6 t ADT: 2,031

Iris Avenue/34 St

Good

Over: Wonderland Creek

Iris Ave and 34th St., Boulder, CO

Built 2017 Load: 36.3 t ADT: 1,937

US 36 ML

Good

Over: DAVIDSON DITCH

2.2 MI SE OF JCT SH 157, Boulder, CO

Built 2015 Load: 36.6 t ADT: 77,000

N 49th St (Cr 51)

Good

Over: Left Hand Creek

0.5 Mi N of Co Rd 34, Boulder, CO

Built 1993 Load: 36.9 t ADT: 191

County Road 103

Good

Over: Middle St. Vrain Creek

200 Ft S of Raymond Store, Boulder, CO

Built 1993 Load: 37.4 t ADT: 112

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

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Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainBridges

Every figure on PlainBridge 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.