Boulder County, CO

311 public highway bridges

Boulder County Bridge Snapshot

Boulder County, Colorado contains 311 public highway bridges in the FHWA National Bridge Inventory. Roughly 33.4% are rated “Good,” 60.5% “Fair,” 2.3% “Poor,” and 2.3% are classified as structurally deficient — the federal designation for spans whose deck, superstructure, or substructure has been rated 4 or below on the 0–9 NBI scale. Structurally deficient does not mean unsafe to cross; it means the bridge is on the priority list for repair or replacement.

Inspections in CO are conducted by certified engineers from the state Department of Transportation on a 24-month cycle, and results are reported back to the FHWA each spring. The list below shows every NBI-tracked bridge in the county, sorted by inventory load rating. Use the “Sort by” controls to surface the lowest-rated spans first, and click any row for full inspection history, traffic counts, and condition trends.

Source: FHWA National Bridge Inventory. See methodology for full definitions.

311

Total Bridges

33.4%

Good

2.3%

Poor

2.3%

Structurally Deficient

Condition Distribution

Good

33.4% (104)

Fair

60.5% (188)

Poor

2.3% (7)

SD

2.3% (7)

All Bridges (311)

Sort:

SH 157 ML

Over: BNSF RR

IN BOULDER, Boulder, CO

Built 1988 Load: 26.5 t ADT: 34,000

SH 7 ML EBND

Over: BOULDER CREEK

ARAPAHOE AVENUE, Boulder, CO

Built 1966 Load: 27.3 t ADT: 15,000

County Road 84W

Over: North St. Vrain Creek

1.0 Mi NW of St Hwy 7, Boulder, CO

Built 1927 Load: 27.6 t ADT: 122

County Road 84S

Over: South St. Vrain Creek

250 ft S of Hwy 7, Boulder, CO

Built 2019 Load: 27.9 t ADT: 67

N. 61st Street

Over: Boulder Creek

1.0 Mi So of Jay Road, Boulder, CO

Built 1986 Load: 28.2 t ADT: 5,789

6th Street

Over: Boulder Creek

0.1 Mi So of Canyon Blvd, Boulder, CO

Built 1978 Load: 28.3 t ADT: 10,000

3rd Ave. EB

Over: GW RR

.15 Mi W of Jct 119, Boulder, CO

Built 1969 Load: 28.6 t ADT: 7,667

Dillon Road

Over: Coal Creek & Ped Tra

0.5 Mi E of McCaslin Blvd, Boulder, CO

Built 1993 Load: 29.1 t ADT: 15,732

SH 7 ML

Over: DRAW

0.35 MI E OF 75th ST, Boulder, CO

Built 1928 Load: 29.3 t ADT: 19,000

SH 157 ML SBND

Over: S BLDR Rd-TBLE MSA Dr

0.9 MI N OF JCT US 36, Boulder, CO

Built 1973 Load: 29.4 t ADT: 19,000

US 287 ML

Over: BOULDER CREEK

3 MI N OF JCT SH 7, Boulder, CO

Built 1985 Load: 29.9 t ADT: 24,000

US 287 ML

Over: DRY CREEK

2.7 MI NO OF JCT SH 52, Boulder, CO

Built 1990 Load: 30.0 t ADT: 24,000

SH 157 ML NBND

Over: SOUTH BOULDER ROAD

0.08 MI N OF JCT US 36, Boulder, CO

Built 1973 Load: 30.2 t ADT: 19,000

SH 72 ML

Over: SOUTH BOULDER CREEK

IN PINECLIFF, Boulder, CO

Built 1979 Load: 30.4 t ADT: 1,500

Martin Street

Over: Saint Vrain River

0.1 Mi N of SH119, Boulder, CO

Built 2009 Load: 30.8 t ADT: 11,759

County Road 103

Over: Middle St. Vrain Creek

100 Ft S of St Hwy 72, Boulder, CO

Built 1927 Load: 31.1 t ADT: 56

Public Road

Over: Coal Creek

.25 M N of Jct US Hwy 287, Boulder, CO

Built 1927 Load: 31.1 t ADT: 10,350

Hygiene Rd (Cr 10)

Over: St. Vrain Creek

1.0 Mi W of Co Rd 31, Boulder, CO

Built 1981 Load: 31.3 t ADT: 502

30th Street

Over: North Goose Creek

At Mapleton & 30th St, Boulder, CO

Built 1994 Load: 32.1 t ADT: 21,233

2nd Avenue

Over: Coal Creek

0.2 Mi South of Williams, Boulder, CO

Built 1992 Load: 32.4 t ADT: 492

WILD BASIN ROAD

Over: NORTH ST. VRAIN CREEK

HWY 7 TO WILD BASIN TRAIL, Boulder, CO

Built 1982 Load: 32.7 t ADT: 75

WILD BASIN ROAD

Over: NORTH ST. VRAIN CREEK

2.1 MILES FROM PARK BOUND, Boulder, CO

Built 1982 Load: 32.7 t ADT: 75

Sixth St (CR 130)

Over: Middle Boulder Creek

.1 Mi S CR 130Eldorado Rd, Boulder, CO

Built 2005 Load: 32.7 t ADT: 106

Nelson Rd (Cr 20)

Over: Boulder Feeder Ditch

1.0 Mi W of Co Rd 39, Boulder, CO

Built 1950 Load: 32.7 t ADT: 2,692

N. 75th St (Cr 25)

Over: Boulder Creek

0.1 Mi S of Jay Road, Boulder, CO

Built 1978 Load: 32.7 t ADT: 8,907

County Road 33

Over: Left Hand Creek

0.3 M N of Oxford Rd (26), Boulder, CO

Built 1980 Load: 32.7 t ADT: 4,344

Niwot Road (Cr 34)

Over: Dry Creek

0.7 Mi E of St Hwy 119, Boulder, CO

Built 1985 Load: 32.7 t ADT: 5,021

Kenosha Rd (CR 38)

Over: Coal Creek

0.2 Mi W of Co Rd 901, Boulder, CO

Built 1965 Load: 32.7 t ADT: 2,305

Cherryvale Road

Over: Davidson Ditch

0.5 Mi N of St Hwy 170, Boulder, CO

Built 1973 Load: 32.7 t ADT: 3,123

Woodland Rd (CR4)

Over: Highland Ditch

1.3 Mi E of 75th Street, Boulder, CO

Built 1976 Load: 32.7 t ADT: 1,163

Independence Ave.

Over: Boulder & Whiterock Dtch

0.4 Mi E of St Hwy 119, Boulder, CO

Built 1973 Load: 32.7 t ADT: 574

Niwot Meadow Farm

Over: Dry Creek No 2

0.2 Mi E of 83rd St, Boulder, CO

Built 2005 Load: 32.7 t ADT: 102

N 41st St (Cr 59)

Over: Left Hand Creek

325 Ft S of Co Rd 26, Boulder, CO

Built 1960 Load: 32.7 t ADT: 226

South Boulder Road

Over: Viele Channel (Ditch)

0.6 Mi E of US Hwy 36, Boulder, CO

Built 1975 Load: 32.7 t ADT: 9,270

S Boulder Road

Over: South Boulder Creek

0.4 Mi E of US Hwy 36, Boulder, CO

Built 1986 Load: 32.7 t ADT: 9,270

CR 62 (Empire Dr)

Over: Coal Creek

0.7 M E of St Hwy 42, Boulder, CO

Built 1935 Load: 32.7 t ADT: 1,080

County Road 9

Over: Boulder Creek

0.3 Mi N of Co Rd 42, Boulder, CO

Built 1960 Load: 32.7 t ADT: 59

County Road 901

Over: Boulder Creek

0.3 Mi N of St Hwy 52, Boulder, CO

Built 1976 Load: 32.7 t ADT: 6,549

Boulder Hills Dr

Over: Boulder Feeder Ditch

50 Ft E of Stirrup Lane, Boulder, CO

Built 1980 Load: 32.7 t ADT: 209

Strath Street

Over: Left Hand Creek

0.2 Mi N of Niwot Rd, Boulder, CO

Built 1970 Load: 32.7 t ADT: 92

Twin Lakes Road

Over: BLDR and Whiterock Ditch

0.2 Mi E of 63rd Street, Boulder, CO

Built 1975 Load: 32.7 t ADT: 1,018

Mc Sorley Lane

Over: South Boulder Creek

0.1 Mi W of Cherryvale Rd, Boulder, CO

Built 1970 Load: 32.7 t ADT: 272

Spring Drive

Over: Davidson Ditch

0.7 Mi S of S. Boulder Rd, Boulder, CO

Built 1970 Load: 32.7 t ADT: 1,022

Folsom Street

Over: Boulder Whiterock Ditch

20 Ft N of Pearl Street, Boulder, CO

Built 1970 Load: 32.7 t ADT: 13,574

30th Street

Over: Empson Ditch

0.59 Mi N of Baseline Rd, Boulder, CO

Built 1963 Load: 32.7 t ADT: 16,733

30th Street

Over: Boulder Creek

0.79 Mi N. of Baseline Rd, Boulder, CO

Built 1963 Load: 32.7 t ADT: 33,663

Juniper Avenue

Over: Elmers Two Mile Ditch

200 Ft E of 26th Street, Boulder, CO

Built 1965 Load: 32.7 t ADT: 666

Kalmia Avenue

Over: Elmers Two Mile Ditch

0.1 Mi W of Folsom Street, Boulder, CO

Built 1973 Load: 32.7 t ADT: 551

Moorhead Avenue

Over: Skunk Creek

0.1 Mi E of 27th Way, Boulder, CO

Built 1970 Load: 32.7 t ADT: 4,313

Moorhead Avenue

Over: Bear Creek: Bike Path

0.4 Mi NW of Table Mesa D, Boulder, CO

Built 1995 Load: 32.7 t ADT: 2,461

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

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Data sourced from official U.S. government datasets. See our methodology for details. Retrieved and formatted by PlainBridges Editorial

Reviewed byPlainbridges Editorial, Plain Bridges Editorial Team · June 6, 2026