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Furbutt After Dark 12-Hour Ultra

50 mi · Ultra · 50K · Marathon · 4.2 mi

May 24, 2026 · Lorton, Virginia, US

Listed Jul 22, 2025

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Until then, open Original listing below for the full source description, and double-check anything important on the organizer’s page.

Original listingFull description from sourceTap to expand · same text as on RunSignup / the official listing

New this year: We are increasing the registration fee to $15 to help cover expenses for the race. Since we are charging a fee this year, note that you will not be expected to bring any food or beverages to share. We will be providing food, water / ice, and Gatorade at the start / finish area. Please bring any additional food or beverages that you anticipate needing during the race for your personal use.

The backyard format is based on Lazarus Lake’s Backyard runs. Runners have one hour to complete the 4.167-mile course. Runners must be in the corral at the top of the next hour ready to start the next loop, or they’re out.

In addition to being a challenging run, Furbutt's After Dark 12-hour Backyard is also a great way to experience the backyard format. This is an excellent opportunity to run your first marathon, 50K or 50-mile distance because the backyard format forces you to rest early and often, which can help you run a longer distance than you thought possible. Please note that to participate in this event, you will need to follow backyard rules: 

Lap Distance: Each lap is 4.167 miles (6.706 kilometers). A completed lap is denoted as 1 Yard. This distance ensures that running 12 laps in 12 hours equals 50 miles.

Time Limit per Lap: Runners must complete each lap within one hour. Any remaining time within the hour can be used to rest, eat, hydrate, or prepare for the next yard.

Start of Each Lap: Yards begin every hour on the hour. Runners who fail to start at the exact time are eliminated.

No Pacing or Assistance on Course: Runners must complete laps without personal aid (one common aid station will be at start / finish area).
Crew support will only be allowed between laps at the start/finish area.

Course Rules: Runners are responsible for monitoring their hydration and should carry a handheld or hydration vest as appropriate for weather conditions. Runners must wear a reflective/light vest and carry a light or headlamp after dark. 

Elimination: Failing to finish a lap within the hour results in elimination OR runners who quit voluntarily or miss the start of a lap are also eliminated.

Winner: The last runner standing must complete their final lap solo to be declared the winner and in this race, there may be multiple runners who run all 12 yards. All others technically receive a DNF ("Did Not Finish") designation.

Safety: Runners are responsible for monitoring their physical condition, hydration level, and fueling. Organizers may intervene if a runner is deemed unfit to continue.

 

Note: This event is inspired by Lazarus Lake, for more information on backyard ultras check out his website https://backyardultra.com/. 

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Full listing on the race page · official details from the source