TMC Earth Day 5K
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About the race
The TMC Earth Day 5K is a run and walk held on the grounds of Biosphere 2 near Oracle, Arizona. The course covers approximately 3.1 miles and runs through private Biosphere 2 property with rolling, hilly sections, mostly on pavement with a brief dirt segment. The route provides desert and mountain views and finishes on the Great Lawn near the Biosphere 2 complex.
Race services include chip timing with a finisher video, age-group and overall awards provided by The Running Shop, post-race refreshments, food trucks, and a morning festival with live music and kids activities. Registrants receive access to Biosphere 2 for self-guided visits through indoor ecosystems such as rainforest, wetlands, savanna grasslands, fog desert, and a living ocean; race entry supports work at the Biosphere 2 Ocean Reef Lab.
There is a reduced youth price option that includes race entry, timing, and Biosphere 2 access but typically does not include a shirt. Souvenir shirts are available to early registrants while supplies last. Packet pickup and in-person registration are offered at The Running Shop before the event and on race morning at Biosphere 2. Running strollers are permitted but runners should be mindful of steep hills; pets are not allowed. The course and venue note accessibility considerations due to hills and a short dirt section. Visit the organization's website for the most recent information.
