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Backyard Ultra
Last runner standing, loop after loop. Filter, sort and register.
Discipline Guide
Backyard ultra racing is a last-runner-standing format invented on Big's Backyard and now a worldwide circuit, where the entire field runs a 4.167-mile (6.706 km) loop every hour on the hour until only one runner remains. The Kinetic Chronicle lists the full circuit, including sanctioned Big's Backyard qualifiers, regional backyard ultras and charity backyard events. Every backyard ultra runs the same loop distance — 4.167 miles — chosen so that 24 loops equal exactly 100 miles, and the race ends when only one runner starts the next loop. Typical events run between 12 and 60+ hours, with the world's elite clearing 80-100+ loops. The directory includes Big's Backyard World Championship qualifiers, regional backyard events and beginner-friendly backyard formats with shorter loops. Filter by state or date to find your next backyard ultra and register directly with the organizer.
How does a backyard ultra work?
All runners start a 4.167-mile loop at the top of each hour. Finish the loop early and you rest until the next hourly start. Anyone who does not start the next loop is out. The race continues until only one runner remains — that runner is the winner, and everyone else is a DNF (did not finish) regardless of how far they ran.
Why is the loop 4.167 miles?
The 4.167-mile (6.706 km) loop distance was chosen so that 24 loops equal exactly 100 miles, and 48 loops equal 200 km. It is short enough that most runners can finish in under an hour for many loops, but long enough that the distance compounds into a serious ultra over a day or more.
How do I qualify for Big's Backyard?
Big's Backyard (the world championship) invites winners of sanctioned qualifier backyard ultras held around the world. Winning or placing high at a sanctioned qualifier is the primary path in. Many regional backyard events are not qualifiers but are excellent training for the format.
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