Patrick Moore / Arizona Sonoran News

For the second year, the infamous Biosphere 2 campus will be the starting line Dec. 14 for the 54th annual Tucson Marathon, a race designed for runners aspiring to compete in the Boston Marathon. 

The event is certified under USA Track & Field as a Boston qualifier, which includes that the course isn’t all downhill. 

The Tucson Marathon last year moved the course route from starting in the Town of Oracle and ending in Catalina, north of Oro Valley, to the Biosphere 2 start point and ending at Pima Community College North on North Shannon Road. 

An estimated 3,000 participants will be competing in either the 26.2-mile full marathon or 13.1-mile half,  said marathon director Jamil Coury, co-owner of Aravaipa Running. 

Last year’s men’s champion Riley Nedrow and women’s champion Obsie Birru won’t be on hand to defend their titles. Nedrow will be preparing for the 2026 Boston Marathon while Birru said she is focusing on teaching. 

Coury, who took over the marathon director position in 2022 from Pam Reed,  described the University of Arizona-owned Biosphere 2, a closed-system environmental research center,   as “an iconic” landmark.

“It’s beautiful, especially the pre-dawn hours when it’s all lit up,” he said.

At last year’s event, both Nedrow and Birru set records.

Nedrow finished in 2:12:47  while Birru’s 2:38:30 set a new women’s record. 

Nedrow’s win came weeks after he competed in the 2024 Mountain West Conference Championships for the University of Wyoming Men’s Cross Country. 

“I gave myself basically a six-week block to train for the marathon, which that’s not really a whole lot of time,” he said.

Apparently six weeks was plenty  

Nedrow blew past Joseph Moreno’s 2023 time of 2:30:09..

“I was so proud of myself and the training that I had put in; also very grateful for the people I had around me, my parents, and my friends back home,” he said. 

But Nedrow’s Tucson Marathon time was just outside of the accepted window to qualify for the Boston Marathon last April. 

Nedrow won’t know until late December or early January of what standing he will be in for Boston. 

The Tucson Marathon is the second Boston Marathon qualifying event in Tucson this year. In November, Garmin, the pioneer of the world’s first running smartwatch, held the inaugural Garmin Marathon Tucson, part of the manufacturer’s nationwide marathon series. 

Registration for the Tucson Marathon closes at 11:59 p.m. Saturday, Dec. 13 To sign up, visit raceroster.com/events/2025/101730/tucson-marathon-events.

Arizona Sonoran News is a news service of the University of Arizona School of Journalism.

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