See the 2026 event

SOLD OUT

All four race distances are SOLD OUT for 2026! We have reached our maximum capacity of 500 runners, including a record 231 runners in the 100 Miler!
JOIN OUR WAITLIST!
We have opened a waitlist for all four distances: 100 Miler, 100K, 50K, and 25K.
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FREE to join! Your credit card will not be charged.
As registered runners drop or defer, spots will be offered to the next person on the waitlist.
If selected, you will receive an email invitation and have 48 hours to accept and complete your registration before your spot is offered to the next runner.
Joining the waitlist does not guarantee entry, but we encourage you to sign up!
Thank you for the incredible support! We look forward to seeing everyone on the Wolf River Trails November 6–7, 2026!

Mamba 100

The Mamba 100 is where endurance athletes come to test their limits on the cleanest, fastest dirt trails in the Southeast. This Western States Qualifier draws runners from across the country to tackle the legendary Wolf River singletrack, chase new PRs, and earn all-new 2026 buckles and medals, including the coveted Sub-20 and Sub-24 hour 100-mile buckles. With world-class photographers capturing every moment, seamless course marking, unmatched community support, and a race weekend that feels more like a celebration than a competition, the Mamba 100 is the event you’ll talk about all year.

Western States Qualifier Race

Mamba 100 Miler is officially a Western States Qualifying Race.
To earn your WSER qualifier, runners must complete the full 100 miles within the 34-hour cutoff.

Packet Pickup

Thursday, November 5 | 2:00 PM – 7:00 PM (CT)
Packet Pickup for all Mamba distances will be held at the Start/Finish Line at the Wolf River Refuge Trailhead on S. Walnut Bend Dr., Memphis, TN 38120.

During Thursday's packet pickup, runners may also set up their 10' x 10' canopy tents for personal aid stations and/or crew use.

Please do not leave food out overnight. Deer, raccoons, and armadillos will happily turn your race supplies into their own late-night buffet!

Friday, November 6 | 5:30 AM – 6:30 AM
Packet Pickup will reopen for 100 Mile runners ONLY. All 100 Mile runners who did not pick up their packet Thursday must arrive during this window to receive their race packet before the 7am start.

Friday, November 6 | Beginning at 9:00 AM
Packet Pickup will reopen for 100K, 50K, and 25K runners and will remain available continuously through the day and night leading up to each race start.

100K runners may pick up their packet anytime beginning at 9:00 AM Friday and before their 7pm race start.

50K and 25K runners may pick up their packets anytime Friday, Friday night, or Saturday morning before their respective race starts.

There is no requirement for 50K or 25K runners to make a separate trip on Thursday or early Friday just for packet pickup. Arrive when it is most convenient for you, as long as you pick up your packet before your race begins.

Refunds, Transfers, and Deferrals

NO REFUNDS
NO BIB TRANSFERS

Entry can be deferred for 100% race credit if requested at least 6 months prior to race day.
Entry can be deferred for 75% race credit if requested at least 4 months prior to race day.
Entry can be deferred for 50% race credit if requested at least 2 months prior to race day.
Entry can be deferred for 25% race credit if requested at least 2 weeks prior to race day.

NO DEFERRALS 2 WEEKS FROM RACE DATE. NO CREDIT WILL BE GIVEN.

Dates and Times

100 Mile - Friday, November 6, 7:00AM
100k - Friday, November 6, 7:00PM
50k - Saturday, November 7, 7:00AM
25k - Saturday, November 7, 9:00AM

Course Description

The Mamba course is centered around a 14-mile loop of flat, fast, and smooth single-track with just a few small hills. Every race starts with a short “lead-in” section before runners enter the main loop.
Race Distances & Loop Breakdown
100 Miler - 7 loops + 2-mile start section / Total ≈ 100 miles
100K - 4 loops + 6-mile start section / Total ≈ 62 miles
50K - 2 loops + 3-mile start section / Total ≈ 31 miles
25K - 1 loop + 1.5-mile start section / Total ≈ 15.5 miles

Trail Sisters Approved Race

The Mamba 100 is proud to be a Trail Sisters Approved Race and is committed to creating a welcoming, equitable, and supportive race experience for women across every distance—the 100 Mile, 100K, 50K, and 25K.

We want women to show up, compete, take chances, chase podiums, attempt new distances, and know that they belong on the starting line.

PREGNANCY & POSTPARTUM DEFERRAL POLICY

We understand that pregnancy and postpartum recovery can change racing plans in ways that cannot always be predicted.

Pregnancy: Any registered runner who becomes pregnant before race day may receive a 100% deferral of their race entry to the following year's Mamba 100. There is no additional deferral fee.

Postpartum: Registered runners who have recently given birth and are unable or do not feel ready to safely participate on race day may also request a 100% deferral to the following year's event. We believe returning to endurance running after childbirth should happen on the runner's timeline—not because of pressure to avoid losing a race entry.

Our goal is simple: pregnancy and postpartum recovery should never force a runner to choose between their health and the entry fee they have already paid.

MENSTRUAL PRODUCTS AT AID STATIONS

Menstrual products will be available at Mamba 100 aid stations throughout the race. These supplies will be provided as part of our normal runner support so athletes can access what they need without having to leave the course or feel uncomfortable asking for assistance.

EQUAL PODIUMS & AWARDS

Women and men will receive equal podium recognition, awards, and prizes across Mamba 100 race distances.

Equal effort deserves equal recognition.

WOMEN AT THE FRONT

At the Mamba 100, we highly encourage women to line up at the front of the starting line.

If you're racing for the win, chasing a podium, going after a PR, or simply want to start confidently from the front—you belong there.

We want young girls and women watching our races to see women standing at the front, competing hard, taking risks, and leading the field.

OUR COMMITMENT

The Mamba 100 is built around community. From our volunteers and aid stations to our medical support and race staff, our goal is to provide an environment where every athlete is treated with respect and receives the support necessary to pursue their goals.

Come race hard. Chase the podium. Chase your first ultra finish. Chase your first 100-mile buckle. Chase Sub-24 or Sub-20.

Women belong at the starting line.
Women belong at the front.
Women belong in ultrarunning.

Mamba 100 video

100k first 6 miles

Aid Stations (breakdown)

All Mamba 100 race distances utilize our fast and runnable 14-mile loop course on the Wolf River Trails. The course has two primary aid station locations: the Bridge Aid Station, which runners pass at approximately miles 4.5 and 9.5 of each full loop, and the Start/Finish Aid Station at mile 14. This setup gives runners access to aid approximately every 4–5 miles throughout the race. Each distance includes an additional beginning segment or out-and-back to achieve the proper race mileage.

100 MILE

The 100 Mile begins with a 2-mile out-and-back before entering the 14-mile loop system. Runners will receive aid at approximately miles 6.5, 10.5, 16, 20.5, 25.5, 30, 34.5, 39.5, 44, 48.5, 53.5, 58, 62.5, 67.5, 72, 76.5, 81.5, 86, 90.5, and 95.5 before returning to the Start/Finish for their 100-mile finish.

100K

The 100K begins with a 6-mile segment before entering the primary loop course. Runners will receive aid at approximately miles 6, 10.5, 15.5, 20, 24.5, 29.5, 34, 38.5, 43.5, 48, 52.5, and 57.5 before finishing at approximately mile 62.

50K

The 50K begins with a 3-mile segment before entering the loop course. Runners will have aid available at approximately miles 3, 7.5, 12.5, 17, 21.5, and 26.5 before returning for their 31-mile finish.

25K

The 25K begins with a 1.5-mile out-and-back before joining the main loop. Runners will pass the Bridge Aid Station at approximately miles 6 and 11 before returning to the Start/Finish for their 15.5-mile finish.

AID STATION SUPPORT

One thing we take very seriously at the Mamba 100 is taking care of our runners. Our aid stations will be fully stocked throughout the race, including the evening and overnight hours. Tailwind will be our primary race hydration, along with water, Gatorade, Coca-Cola products, and additional drink options.

Runners can expect a large selection of traditional ultra food with plenty of sweet and salty choices. Throughout the race, offerings will include items such as pizza rolls, cheese sticks, grilled cheese, cheese quesadillas, peanut butter & jelly sandwiches, chicken nuggets, chips, mashed potatoes, candy, chocolate, and plenty of additional snacks and nutrition options.

As our 100 Mile and 100K runners move into the evening and overnight hours, we'll begin serving additional hot and more substantial food. Expect items such as hamburgers, hot dogs, hot soups, ramen, broth, lasagna at the Start/Finish Aid Station, and additional rotating hot-food options throughout the night.

There will be more food than you know what to do with, and our goal is to keep every aid station well stocked from the beginning of the race until our final runners come through.

The Start/Finish Aid Station serves as our primary runner-support hub. Depending on your race distance and applicable race rules, runners will have access to their crew, drop bags, personal supplies, personal aid stations, and 10' x 10' canopy tents. For our longer-distance runners, returning to Start/Finish throughout the race gives you repeated access to your gear, nutrition, crew, and personal supplies.

From the first mile to the final mile, our job is to take care of you, keep you fueled, and help you keep moving toward that Mamba finish line.

100 miler - first 1.8 miles

50k - first 3 miles

25k - first 1.5 miles

Awards, Medals, and Buckles

• Top 3 Male & Female in every race distance receive awards.
• 100 Mile:
– Sub-20 Hour buckle
– Sub-24 Hour buckle
– All 100-mile finishers earn a custom Mamba buckle
• 100K: All finishers earn a 100K buckle
• 50K & 25K: All finishers earn finisher medals
All buckle and medal designs are brand-new this year.
Note: We do not offer drop-down buckles or medals for any distance. Every award is earned for the race you complete.

14 mile loop

Locations

The Mamba 100 is held at the Wolf River Refuge Trailhead on S. Walnut Bend Rd., Memphis, TN 38120. This is also the location for Packet Pickup on Thursday, November 5th from 2:00–7:00 pm.

The trailhead sits just off Germantown Parkway, directly across the street from the Shell Gas Station and Lowe’s, making it easy and convenient to find.

Race Rules

Mamba Trail Runners — Race Rules
Every runner is responsible for knowing and following all rules.
These are standard ultra rules — not overly restrictive.
Most issues happen from misunderstanding, not cheating.

General Race Rules
No dogs allowed.
No dropping down in distance during the race.
No muling — runners must carry their own gear, food, and water.
Crew can only access their runner at the Start/Finish line area.
Crew may not assist or access their runner anywhere else on the course.
Trekking poles are allowed — be courteous around others.
Pacers must run the entire 14-mile loop with their runner.
Pacers and crew must follow all rules — see “Aid Station & Pacers” for full details.
No littering at aid stations, on trails, or at the finish line.
No course cutting or shortcuts — stay on the marked course.
If you don’t follow the course as marked, you will not receive an official time or award.
Race must be completed on foot only (no bikes, scooters, skateboards, roller skates, vehicles, sled dogs,).
Headphones are allowed, but remove them when approaching aid stations.
Be respectful when runners approach to pass — stay aware of your surroundings.
You are responsible for the behavior of your crew and pacers.
Rude or disrespectful behavior toward volunteers, staff, other runners, hikers, or cyclists can result in disqualification.
If you receive an IV, oxygen, or have a serious injury, your race is over.
Drop bags are allowed at the Start/Finish line area only.
No stashing of supplies along the course — use official drop bag location only.
No cheating. If you have to ask if it’s cheating… it probably is.

🧍 Age Requirements
100 Miler: 18+
100K: 18+
50K: 16+ (Parent/Guardian must sign waiver)
25K: 13+ (Parent/Guardian must sign waiver)

Sponsors

We would love for you or your company to sponsor the Mamba 100. We have many different types of sponsorships available. Please reach out to mambatrailrunners@gmail.com if interested. Sponsoring the race will guarantee you a 10x10 canopy tent spot right by the Start/Finish line of the race.

Pacers

Pacers are permitted for the 100 miler and the 100k distances only.
-No pacers allowed for the 50k and 25k distances.
-One pacer at a time per runner
-Pick-up location: Pacers may only begin from the Start/Finish Aid Station and run the entire loop with their runner.
-100-mile runners: Pacers may begin at Loop 4.
-100k runners: Pacers may begin at Loop 3.

Pacer Rules:
-Pacers must sign a release form and pick up a pacer bib at packet pickup or before their pacing duties.
-Pacer must stay with their runner at all times.
-Pacers must enter and exit with their runner at all times (aid stations)
-No muling: Pacers may not carry water, food, lights, or gear for their runner.
-Pacers may receive aid at aid stations and carry their own supplies.
-If a runner drops, the pacer must stop as well.
-In case of emergency, a pacer may leave a downed runner only to seek aid at the next aid station. The runner will be withdrawn from the event for safety.
-Pacers are companions - not leaders. Runners are responsible for navigating the course.

Photographers

We’re bringing in two of the absolute best.
Jenny Thorson and Misty Herron will be the official photographers of the race, capturing every gritty, joyful, and unforgettable moment. These two are masters of their craft—their work has been featured in major publications, ultra-running magazines, and more.
And the best part? Every single photo from the race is 100% free for all runners to download, share, and keep.
Get ready for world-class photos that tell the full story of your race experience.

Accommodations

The Wolf River Refuge Trailhead (start / finish line) is located right off Germantown Parkway and there are numerous hotels, restaurants, grocery stores, gas stations, etc. all along Germantown Parkway. Everything you can possibly need is within a mile or two from the Trailhead.

Holiday Inn Express & Suites 7784 Wolf Trail Cove Germantown, TN 38138 (901) 309-6700
Courtyard Memphis/Germantown 7750 Wolf River Blvd. Germantown, TN 38138 (901) 751-0230
Homewood Suites 7855 Wolf River Blvd. Germantown, TN 38138 (901) 751-2500
Hampton Inn & Suites 1680 S. Germantown Rd. Germantown, TN 38138 (901) 309-0555

RV camping is also available at Agricenter International. The RV Park offers sites with sewer, 30-amp & 50-amp electrical hook-ups, water, dump station, restrooms, shower, and laundry facilities. The RV Park at Agricenter is the perfect location if you plan on bringing or renting an RV. The main car parking area for Viper is right across the street from the RV campground.Walmart and grocery stores are ~2 miles away.

Restaurants - There are many restaurants packed up and down Germantown Parkway

Breakaway Running Store - less than a mile away for all your running needs and gear

Drop Bags

Drop bags are only permitted at the Start/Finish line area. For runners who don’t have their own personal canopy, we’ll have a dedicated 10x30 grey “Runners Tent” set up for you. You’re welcome to place your gear inside and access it after each 14-mile loop. This space will be covered, easy to find, and open throughout the race to keep you organized and moving strong.

Crew / Personal Aid Station rules

No dog pens allowed.
No open camp-fire flames. Solo stoves are allowed.
No loud music at any time.
Canopy tents should be 10x10. Please don’t use a 10x20 canopy tent for one person.
Camping tents are allowed.
No overnight camping at the Start/Finish line on Thursday night (November 6). Our team will be working through the night preparing for the race.
Do not leave food out on Thursday evening. It will be gone by Friday morning.
You may drive to the parking lot and unload on Thursday to set up your canopy tent.
Tent setup begins at 1 PM on Thursday.
Please take your tent and belongings with you when you leave on Saturday. Any leftover tents, tables, chairs, coolers, or other items will be removed on Saturday evening.
Clean up your trash and take it to the dumpster located in the back of the parking lot.
We would like to avoid having to create an official dog policy, so please use good judgment.
No dogs that bark constantly or show aggressive behavior.
If you bring a dog, it must:
Be on a leash at all times.
Remain inside your canopy tent.
Be cleaned up after — owners are responsible for picking up and disposing of all waste.
Runners are responsible for the behavior and conduct of their crew.
No drug use or smoking illegal substances.
Be respectful of your neighbors and other participants. Cheer on runners as they pass.
Place your tent directly next to your neighbor’s tent. If you leave a 5-foot gap, we will ask you to move it so there’s no space between tents.

For More Information

For more information join these pages:
Facebook Group: Mamba Trail Runners (this page is packed with information from group challenges to a runner's bio.)
Instagram: Mamba Trail Runners
Youtube: Mamba Trail Runners

Event's current local time: 12:03 PM CT