Junko Kazukawa is a Japanese-born women's ultra running pioneer best known for having finished the Leadville 100-mile race 10 times. Junko is a two-time breast cancer survivor with more than three decades of experience in health, fitness, and training. She currently works as an ultra endurance coach with Boundless. Junko lives and trains in Denver, Colorado, and has completed 24 100-mile trail races so far, including Leadville, UTMB, Mt. Fuji, Ultra Fiord in Patagonia. She's the first female to finish the Grand Slam of ultra running in 2015. She was Lead Woman three times, in 2014, 2015 and 2024. This means she completed all six events in the Leadville Race Series in the span of two months in the nation’s highest city, including a trail marathon, a mountain-bike race, the Leadville Trail 100 Run, and more. She was the 2015 Sports Woman of Colorado and voted as the Colorado resident badass in 2017.