Boulderthon: Downtown Boulder Marathon

USATF Certified

Sunday, September 27, 2026

Boulder, Colorado

USATFCourse

Course Information

USATF Certified Course

CO25005DT · Expires 2035

Certified Course Name

Boulderthon Half Marathon

Net Drop

-0.24

m/km

Separation

1.3%

start to finish

This course is relatively flat with minimal net elevation change. Loop course — start and finish are close together.

View USATF Course Map (PDF)

Race Details

Race Day

Sunday, September 27, 2026

Course

Loop

Also Offers

26.2M10K5K run | kids run

Registration

Race Website

Official race information

Historical Weather

☀

Avg High

77°F

☽

Avg Low

48°F

☂

Precip

0.02 in

🍃

Wind

8.9 mph

47% humidity·Based on 5-year historical data

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Course Information

USATF Certified Course

CO25005DT · Expires 2035

Certified Course Name

Boulderthon Half Marathon

Net Drop

-0.24

m/km

Separation

1.3%

start to finish

This course is relatively flat with minimal net elevation change. Loop course — start and finish are close together.

View USATF Course Map (PDF)

Race Details

Race Day

Sunday, September 27, 2026

Course

Loop

Also Offers

26.2M10K5K run | kids run

Registration

Race Website

Official race information