Bad Ass Backyard Ultra - Rio Linda, CA

The Bad Ass Backyard Ultra (B.A.B.U.) is an endurance running event held at Dry Creek Parkway in Rio Linda, California, near Sacramento. Participants run a 4.16-mile loop every hour, starting on the hour, with each loop called a "yard." Runners must be ready to start each new loop on time or face elimination. The event continues until only one runner remains, who has completed the most loops.

Originally launched in 2023 as a fatass event, B.A.B.U. became an official backyard ultra in 2024 through a partnership between Skybreaker Racing and Auburn Area Trail Runners, now under Singletrack Running. It offers qualification for national and world backyard ultra championships. Visit the organization's website for the most recent information.