World's Slowest Marathon - Denver

JUL
17
2026
A 24 hour event to cover 26.2 miles in repeated segments while fundraising for Neighbors, a Denver nonprofit supporting people experiencing homelessness. Several community runs include partner refreshments and amenity offerings.
Fri 17 Jul 2026
26 miles 4 miles

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World's Slowest Marathon: Running for a better Denver

The event is a 24 hour effort to cover 26.2 miles while raising funds for Neighbors, a Denver nonprofit that does frontline outreach for people experiencing homelessness. The marathon distance is completed through repeated running segments that occur every four hours over a 24 hour period.

Organizers plan a mix of solo segments and community runs at several points during the 24 hours. Community runs are described as open to everyone and are followed by partner-hosted refreshments and activities, including post-run beers, coffee and bagels, and access to a sauna and cold plunge provided by local partners. Organizers ask for a minimum $25 donation to Neighbors for participation in the community runs.

The event base is ISO Health Physical Therapy & Wellness in Denver, and several community runs take place on a route around Sloan's Lake. The stated fundraising goal is more than $6,000 to help supply food, basic items, and outreach services for Denver's unhoused neighbors. Registration and donation options are available through the event organizer and associated fundraising pages. Visit the organization's website for the most recent information.

26 mi
Full Marathon (24 Hours)
4 mi
Loop
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