Javelina Jundred Race Guide
The Javelina Jundred is held each Jalloween weekend in late October, with the 2025 event scheduled for October 25–26. This unique festival of ultrarunning takes place in McDowell Mountain Regional Park near Fountain Hills, Arizona, where runners embrace the desert’s vibrant Halloween spirit while tackling either 100 miles, 100 kilometers, or the 31 K “Jackass” night loop. The weekend’s timing ensures warm daytime temperatures followed by cool desert evenings, creating dramatic weather swings that test both physical endurance and mental toughness. Participants are encouraged to dress in costume, turning the aid stations and trail segments into lively party scenes. With roots stretching back two decades, this event celebrates community and camaraderie as much as endurance.
How to Qualify and Register
Entry into the 100-mile and 100-kilometer distances is managed through UltraSignup, with registration opening January 1 each year. Prospective runners must complete an online application and pay the entry fee—typically between $700–$900—to secure a spot. A waitlist system fills any vacancies on a first-come, first-served basis, and those selected from the waitlist must confirm within 72 hours to avoid forfeiture. The 100-mile race also serves as a qualifier for the Western States 100 lottery, requiring finishers to complete the distance in under 30 hours. For those seeking a charity bib, a fundraising commitment of $4,000 for the 100 mile or $3,000 for the 100 K option grants entry via the Wander Project program, with registration codes issued upon reaching 75 percent of the fundraising minimum.
Particular Challenges
Runners face significant challenges from the Sonoran Desert environment and the looped course format. Daytime highs can soar into the mid-80s, while nighttime lows dip into the 40s, demanding adaptable clothing and vigilant hydration strategies. The five-loop design means returning to the start/finish area multiple times, which can disrupt rhythm and require careful pacing to avoid early overexertion. Under desert skies, sand, rocks, and loose gravel complicate footing, while sandy washes collect at trail edges, increasing energy expenditure. The festive atmosphere—with costumed runners, themed aid stations, and music—can be both motivating and distracting, requiring runners to stay focused on nutrition, pace, and cutoffs.
Course Format
The 100-mile distance begins with one 22.3-mile loop followed by four identical 19.45-mile loops, summing to just over 100 miles. The 100 K option uses the first three loops of the 100-mile layout, totaling approximately 62 miles. The 31 K “Jackass” night trail is a single 19.45-mile circuit on the same trail network, designed for runners seeking a shorter, festive night-time experience. Each loop starts and finishes at Javelina Jeadquarters, with four on-course aid stations—Javelina Jeadquarters, Coyote Camp, Jackass Junction, and Rattlesnake Ranch—positioned around the Pemberton, Cinch, and Escondido trails. Runners pass through Javelina Jeadquarters at the end of each lap, allowing crew access only at the start/finish area.
Elevation Profile
Runners in the 100-mile race ascend a total of approximately 6,296 feet, with 6,243 feet of combined climbing and descending according to outside reports. The course’s highest point reaches 2,486 feet above sea level, while the lowest point sits at around 1,623 feet, yielding gentle rolling hills rather than severe mountain climbs. Each loop features roughly a 600-foot climb from Javelina Jeadquarters to the loop’s apex on the Escondido Trail, with subsequent undulating terrain on the Pemberton and Cinch Trails. The net elevation gain per 22.3-mile first loop is slightly higher, with later 19.45-mile loops offering around 1,200 feet of climb and descent apiece.
Terrain Breakdown
The trail surface is predominantly groomed desert singletrack, with segments of hard-packed granite, loose rocks, and occasional sandy washes. Approximately 85 percent of the course is singletrack, weaving through saguaro-dotted desert expanses and offering technical footing at times. Dirt roads or old Jeep paths make up the remaining 15 percent, providing brief opportunities to settle into a rhythm. Sand collects in wash crossings and low-lying sections, demanding vigilance and a slightly wider gait to maintain stability. The mixed surfaces require runners to balance speed with caution, especially when fatigue sets in on later loops.
Time Limit and Cutoffs
The overall time limit for the 100-mile race is 30 hours, with runners required to finish before 6 PM the following day to be considered official finishers. The 100 K race must be completed within 29 hours. While there are no published intermediate cutoffs at aid stations, the longest stretch between resupplies is 6.6 miles between Rattlesnake Ranch and Javelina Jeadquarters on the first loop, and 6.5 miles between Coyote Camp and Jackass Junction on subsequent laps. Runners missing these informal pacing markers risk falling behind the necessary average pace of roughly 20 minutes per mile, making proactive pacing and time checks critical throughout the night and early morning hours.
Aid Stations
Runners encounter five staffed aid stations on the 100-mile course, spaced roughly every 19 to 22 miles around the looped course. These stations provide water, electrolytes, snacks, and hot food, with volunteers ready to help refill bottles and offer encouragement. Competitors may access crew only at the start/finish area, where drop bags can be stored and retrieved between loops. Each aid station features porta-potties and sheltered rest areas, allowing runners to change clothes or take brief breaks. The spacing means some stretches exceed six miles without support, so pacing strategies must account for those longer gaps.
Mandatory Gear
All participants must carry safety and survival gear throughout the race. Required items include a headlamp with fresh batteries, a reflective safety vest, a whistle, and a waterproof emergency blanket. Runners also must have enough water-carrying capacity—usually a pack or vest that holds at least two liters—and sufficient calories to last between aid stations. In cooler desert nights, extra layers such as a long-sleeve shirt or windbreaker become crucial for preventing hypothermia. Race officials inspect mandatory gear at the start and may perform spot checks at aid stations.
Crew & Pacing
Crew support is strictly limited to the main aid station at Javelina Jeadquarters, where runners return at the end of each loop. No vehicles or crew members can access on-trail aid stations, emphasizing self-sufficiency on the desert course. Pacers are allowed from mile 50 onward in the 100-mile distance, but they must check in at the start/finish before joining their runner. Pacing duties focus on navigation assistance, morale boosting, and occasional hand-feeding rather than carrying extra gear. Vehicle access to the park is restricted to predesignated parking lots, so crews must plan drop-off and pickup times carefully.
Navigation
The entire course is marked with bright pink or orange surveyor tape tied to bushes and rocks, along with reflective glow sticks in key turns for night visibility. Volunteers confirm markings multiple times before race day, but runners are encouraged to carry route notes or GPS devices preloaded with the course track. A handheld GPS unit or smartphone with offline mapping is recommended for extra insurance against any faded markings or unexpected unmarked areas. Checkpoints at each aid station record runner bib numbers, ensuring that everyone passes through in the correct sequence. Although the looped format simplifies navigation by repeating the same course, fatigue can still make following tape challenging after dark.
Finish Rates
Over the last several years, approximately 60 percent of entrants complete the full 100-mile distance within the 30-hour cutoff. The 100-kilometer option sees a higher success rate, with roughly 75 percent of starters finishing under the time limit. The shorter 31-K Jackass Loop attracts many first-time ultrarunners, who finish at an even higher rate of about 90 percent. Desert heat during the day and cold nights contribute to attrition, with most drop-outs occurring on the second loop as runners grapple with muscle fatigue and blisters. The festive atmosphere and supportive volunteers help boost morale, often inspiring late-race comebacks.
Special Features
Javelina Jundred is as much a costume party as a race, with runners dressing up in creative Halloween outfits that range from superheroes to sci-fi icons. Unique awards such as Best Costume and Spirit of Javelina recognize the most imaginative and supportive participants. Finishers earn a distinctive glow-in-the-dark buckle shaped like a javelina skull and a limited-edition technical shirt. The event’s nighttime loop, the Jackass 31K, offers an especially eerie glow-stick-lined experience under the stars. Live music and themed aid stations create a festive environment that sets Javelina apart from more austere ultras.
Previous Winners
Top runners in recent years include seasoned ultrarunners who have posted finishing times between 18 and 21 hours on the 100-mile course. The men’s course record stands at just under 17 hours, set by a competitor who tackled the loops at a sub-10-minute-per-mile pace. On the women’s side, the fastest finish has been around 19 hours, demonstrating the event’s competitive yet friendly vibe. The 100K winners typically cross the line in 9 to 11 hours, blending speed on rolling desert terrain with efficient transitions at aid stations. Many past champions have returned multiple times, drawn by the unique mix of challenge and celebration.
Official Contact Information
Race director details and general inquiries go through Aravaipa Running, the event organizer based in Tucson, Arizona. Runners can email questions to info@aravaiparunning.com or call the office during business hours at (520) 207-8848. Event updates, course maps, and official communications are posted on the Javelina Jundred website in the weeks leading up to the race. Social media channels such as the Javelina Jundred Facebook page and Instagram handle also provide timely announcements on weather, course changes, and volunteer opportunities. For urgent race-day questions, the on-site race headquarters phone number is listed in the final athlete packet distributed at packet pickup.