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September 4 - 20, 2024 • Dousman, Wisconsin
Ottawa Lake State Park

~ 10x / 5x / 4x / 3x / 2x / 1x ANVIL ~

Mammoth Black


Solo Continuous Anvil Triathlon
Traditional Swim, Bike, Run Format.
  - 10x ($4,200) | 336 hour time limit.
    24 mile swim, 1,120 mile bike, 262 mile run
  - 5x ($2,750) | 132 hour time limit.
    12 mile swim, 560 mile bike, 131 mile run
  - 4x ($2,200) | 96 hour time limit.
    9.6 mile swim, 448 mile bike, 104.8 mile run  
  - 3x ($1,500) | 60 hour time limit.
    7.2 mile swim, 336 mile bike, 78.6 mile run
  - 2x ($1,200) | 36 hour time limit.
    4.8 mile swim, 224 mile bike, 52.4 mile run
  - 1x ($850) | 17 hour time limit.
    2.4 mile swim, 112 mile bike, 26.2 mile run

Solo 1 Per Day Anvil Triathlon
1 Full Distance Triathlon Per Day Format.

  - 1x10 ($4,200) | 24 hour time limit per day.
  - 1x5 ($2,750) | 24 hour time limit per day.

  - 1x3 ($1,500) | 24 hour time limit per day.

Relay Continuous Anvil Triathlon
Relay Team (2 - 3 Athletes Per Team)
  - 10x ($1,500 per person) | 336 hour time limit
     24 mile swim, 1,120 mile bike, 262 mile run

  - 5x ($1,500 per person) | 132 hour time limit.
    12 mile swim, 560 mile bike, 131 mile run

  - 3x ($1,000 per person) | 60 hour time limit.
    7.2 mile swim, 336 mile bike, 78.6 mile run

  - 2x ($750 per person) | 36 hour time limit.
    4.8 mile swim, 224 mile bike, 52.4 mile run

Solo Continuous Aquavelo
Swim, Bike Format.
  - 10x ($4,000) | 198 hour time limit.
    24 mile swim, 1,120 mile bike

  - 5x ($2,250) | 84 hour time limit.
    12 mile swim, 560 mile bike

  - 3x ($1,300) | 42 hour time limit.
    7.2 mile swim, 336 mile bike

  - 2x ($1,000) | 26 hour time limit.
    4.8 mile swim, 224 mile bike

Solo Continuous Duathlon
Bike, Run Format.
  - 10x ($4,000) | 300 hour time limit.
    1,120 mile bike, 262 mile run

  - 5x ($2,250) | 126 hour time limit.
    560 mile bike, 131 mile run

  - 3x ($1,300) | 57 hour time limit.
    336 mile bike, 78.6 mile run

  - 2x ($1,000) | 34 hour time limit.
    224 mile bike, 52.4 mile run


All race registrations are completed online. We do not accept paper forms, do not offer race day registrations and do not accept payment from other services like PayPal or Venmo. You may register online by clicking here.

All athletes racing the double or greater distance (solo and team members) are required to have our Medical Release Form signed by a licensed doctor. This form must be submitted to our race director via email one month prior to the race start.
s may download the Medical Release Form here.

We understand the financial commitment it takes to register for an event of this distance. We do offer options for payments. If you need to make split payments, please email and let him know which option you prefer.

  - Option 1: Pay half now and half no later than 60 days out from the event.
  - Option 2: Pay 1/3 now, 1/3 no later than 120 days out from the event and the final 1/3 no later than 60 days out from the event. 

  *please note: these race payment options are only available for those races with a registration fee over $2,500.

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Mammoth Black

This event is produced by Mammoth Endurance, the leaders in ultra triathlon racing in the United States. Our Mission at Mammoth is to organize the highest quality and most thoughtful ultra triathlons in the world. We're a small, family owned and operated business with over 30 years of experience producing endurance events around the country. 

You can use these links to meet our team or read about our company values.

Make sure you check out The Mammoth Podcast to find inspiration to keep working hard towards your goals.

This event is sanctioned by the World Ultra Triathlon Association (WUTA). WUTA provides structure, guidance, and resources, at no charge, to race directors and athletes who are organizing or participating in ultra-triathlon events. All athletes registered for any distance further than a 140.6 mile full distance triathlon are eligible to earn a World Ultra Triathlon finishers pin. WUTA is working towards becoming a 501(c)(3) registered non-profit and is 100% volunteer driven.

Visit (coming soon) for additional details and to learn more about the World Ultra Triathlon Association.

This race is sanctioned by USAT (United States Triathlon Association). All athletes are required to belong to USAT, either with a yearly membership or by purchasing a one-time “day use” license. If you do not hold a USAT membership you will be given the opportunity to purchase a one day pass during the online registration process. 

Visit for additional details and to learn more about the United States Triathlon Association.


Mammoth Endurance and WUTA have an agreement with the United States Anti-Doping Agency (USADA). USADA personnel are at each event to collect, test and remit results for 2 - 3 randomly selected athletes. Under certain conditions an athlete may be pre-determined for testing prior to the race. Testing is carried out at one of the two Olympic Certified Laboratories in the United States. Testing with USADA ensures our sport is receiving the highest standard in Anti-Doping testing. 

Visit for additional details and to learn more about the United States Anti-Doping Agency.



Since 1985. Home Of The Original Ultra-Triathlon.



Our athlete guide contains everything you will need to know for your event. We make this guide available to you at all times so you can plan ahead and be as prepared as possible for you event. It is the athletes responsibility to read the athlete guide in its entirety and familiarize yourself with the rules, courses, schedule and other details pertaining to the event.

We will post the current years Athlete Guide 1
 month prior to the start of the race. 

It is the athletes responsibility to read the athlete guide in its entirety and familiarize yourself with the rules, courses, schedule and other details pertaining to the event.


WIA Athlete Guide


Tuesday - September 3, 2024
10:00am - 5:00pm • Course / village setup.

Wednesday - September 4, 2024
10:00am - 12:00pm • 10x continuous athlete check-in.
12:30pm - 1:30pm • 10x continuous athlete meeting & lunch.

Thursday - September 5, 2024
6:30am • 10x continuous athlete roll call.
6:50pm  • U.S.A. National Anthem.

7:00am • 10x continuous race start.

Friday - September 6
, 2024
1:00pm • 10x continuous swim cutoff.

Saturday - September 7
, 2024
10x continuous race in progress.

Sunday - September 8, 2024
10:00am - 12:00pm • 1x10, 1x3, 3x, 2x, 1x athlete check-in.
12:30pm - 1:30pm • 1x10, 1x3, 3x, 2x, 1x athlete meeting & lunch.

Monday - September 9, 2024

6:30am • 1x10, 1x3, 3x, 2x, 1x continuous athlete roll call.
7:00am • 1x10, 1x3, 3x, 2x, 1x race start.
11:00am • 1x continuous swim cutoff.
12:00pm • 2x continuous swim cutoff.
3:00pm • 3x continuous swim cutoff.

8:00pm • 1x continuous bike cutoff.

Tuesday - September 10, 2024
12:00am • 1x continuous run cutoff.
am •  1x10, 1x3 athlete roll call.
7:00am • 1x10, 1x3 race start (day 2).
9:00am • 2x continuous bike cutoff
7:00pm • 2x continuous run cutoff.

Wednesday - September 11
, 2024
1:00am • 3x continuous bike cutoff.
6:45am •  1x10, 1x3 athlete roll call.
7:00am • 1x10, 1x3 race start (day 3).
7:00pm • 3x continuous run cutoff.

Thursday - September 12, 2024
6:45am •  1x10 athlete roll call.
7:00am • 1x10 race start (day 4)
10:00am - 12:00pm • 1x5, 5x, 4x athlete check-in.
12:30pm - 1:30pm • 1x5, 5x, 4x athlete meeting & lunch.


Friday - September 13, 2024
6:30am • 1x10, 1x5, 5x, 4x athlete roll call.
7:00am • 1x10 (day 5), 1x5, 5x, 4x race start.
1:00pm • 10x continuous bike cutoff.

5:00pm • 4x continuous swim cutoff.
7:00pm • 5x continuous swim cutoff.

Saturday - September 14, 2024
6:30am • 1x10, 1x5 
 athlete roll call.
7:00am • 1x10 (day 6), 1x5 (day 2) race start.

Sunday - September 15, 2024
6:30am • 1x10, 1x5 
 athlete roll call.
7:00am • 1x10 (day 7), 1x5 (day 3) race start.
10:00pm • 4x continuous bike cutoff.

Monday - September 16, 2024
6:30am • 1x10, 1x5 
 athlete roll call.
7:00am • 1x10 (day 8), 1x5 (day 4) race start.
7:00pm • 5x continuous bike cutoff.

Tuesday - September 17, 2024
6:30am • 1x10, 1x5 
 athlete roll call.
7:00am • 1x10 (day 9), 1x5 (day 5) race start.
7:00am • 4x continuous run cutoff.

Wednesday - September 18, 2024
6:30am • 1x10 
athlete roll call.
7:00am • 1x10 (day 10) race start.
7:00pm • 5x continuous run cutoff.

Thursday - September 19, 2024

7:00am • 10x continuous run cutoff.
2:00pm • All equipment must be removed from park.

Friday - September 20, 2024
1:00pm - 4:00pm • Awards Ceremony & Lunch.

Breakfast is served every other day at 6:45am
Lunch is served daily at 12:30pm
Dinner is served daily at 5:30pm
Late Snacks are served every other day at 10:00pm

*Food service times are approx. as we cook from scratch.



We are very excited to host the the DECA once again here in the United States. This is only the third time in the history of the sport that an event of this distance has taken place on American soil. The event is made up of a 24 mile swim, 1,120 mile bike and a 262 mile run. Athletes must complete the distance in under 336 hours. To date, only 166 people in the world have ever completed the distance.

The event is sanctioned by the United States Triathlon Association (USAT) and World Ultra Triathlon Association (WUTA). Eligible athletes will be rewarded both regional and national points from WUTA. The United States Anti-Doping Agency (USADA) will be conducting drug tests of the winners to ensure our sport remains clean. 

DECA podium awards will be handed to the top three male and female finishers in the double distance at the athletes banquet.

1st place - male / female
2nd place - male / female
3rd place - male / female

All rules set in place by the sanctioning bodies must be followed for the athlete to be eligible for awards. Any athlete or crew who does not follow the rules laid out in the rulebooks and crew conduct documents will be disqualified without exception.

We wish all athletes the very best of luck, a healthy season of training and safe travels to the race.

See you at the DECA!


Our courses consist of shorter loops. The distance of our events require extra safety measures be taken to ensure athletes are cared for and able to receive medical help if needed while on course. These shorter loops allow for your family or crew to be much more involved in your race, resulting in an overall more enjoyable experience for athletes and their support crew. 

The courses are well marked / manned by volunteers during the event. Try it before you bash it - we guarantee you'll find the shorter loops helpful and more enjoyable during your event.

WIA Course


10x: 120 loops / 5x: 60 loops / 4x: 48 loops / Triple: 36 loops / Double: 24 loops / Single: 12 loops

The Swim course is a 0.20 mile loop (1056 feet/322 meters). We will be swimming in an open water, non-motorized lake for all race categories. If we experience lightning before or during the swim portions of your race, we will have a backup pool to swim in. Athletes will call out their race number to our timers on the beach in between each lap. Multiple floating stations will be available to athletes allowing you to leave hydration and food for easy access during the swim.

Each athlete will be given, and is required to wear, a swim cap to wear during the swim. To be used, worn throughout the swim.

In the evening hours, the swim buoys that line the course will be lit up for visibility. The timing tent will also be illuminated for sighting so our swimmers can see where they are headed. Each athlete will be given, and is required to wear, a swim buoy that illuminates at night during the evening hours. It will also be required that each swimmer who is in the water overnight have a crew or support member present on the beach area to help keep eyes on their swimmer. 

Lifeguards and volunteer kayakers will be present on the water throughout the entirety of the swim.

The water temperature at this time of year is typically a comfortable 70 - 72 degrees Fahrenheit. The lake water is mostly clear with a sandy bottom. You'll see fish and turtles under water during your swim. There are some weeds on the north side of the lake but our swim course stays south, closest to the beach, avoiding the weedy areas of the lake. 

Swim Course.png
Swim Course.png


10x: 200 loops / 5x: 101 loops / 4x: 80 loops / Triple: 60 loops / Double: 40 loops / Single: 20 loops


The bike course is an open road, out and back course on newly paved roads. The course is designed to be easy on the athlete with minimal hills and a very smooth road surface to ride on. At the end of the course, riders will make a 180-degree turn to make their way back to the race village. Volunteers will be present on course throughout the entirety of the event. We will have a restroom available at the bike turnaround. 

All riders are required to have a white headlight and red rear light on their bike while riding in the overnight hours.

The bike course is on open roads meaning you will encounter light vehicle traffic. Signage will be placed along the roadway to notify motorists of the event.

The bike segment is a 5.58 mile (8.890 kilometer) out and back. You will start the bike in the village area.

We have calibrated the course with the same measuring equipment used by the Olympic committee (it is called a Jones Counter) so we are accurate on the mileage. Remember, GPS data from your watch, with long distances and multiple loops, will often be incorrect over time. Our courses are carefully marked and measured. Do not rely on your satellite GPS watch as an accurate measurement.

Road bikes must be in good working order. Remember to inspect your bikes before the race so you do not have any mechanical surprises on the bike course. You may use more than one bike during the race.

You must wear an ANSI/Snell approved bike helmet during the bike course and have it buckled at all times when touching your bike. YOU MAY NOT DRAFT during this event. While on the bike segment, cyclists shall not work together to improve performance, efficiency, or position by teamwork or other joint conduct. All cyclists must assume and maintain a staggered riding position relative to the cyclists directly ahead. A variable time penalty shall be imposed for any violation of this. You may stop or walk your bike, but no time adjustments will be made.

We will have course signage out notifying motorists of the event. At the end of the day, cars are bigger than bikes so please stay alert and be aware of your surroundings.

No headphones are allowed. While you may carry a phone, you cannot use it as a communication device.


10x: 260 loops / 5x: 130 loops / 4x: 104 loops / Triple: 78 loops / Double: 52 loops / Single: 26 loops

The run segment takes place on asphalt road. The run course is a 1.00769 mile (1.621719 kilometer) loop course.


The paved run course is designed specifically to give your crew three easy points of access per loop to you to help with fueling when needed. The course stays inside the park and campground at all times. There are multiple bathroom opportunities along the course. The run course is somewhat exposed so be prepared for all weather conditions.You must use a flashlight/head light for the run section once it gets dark as well as a flashing red light on your back for greater visibility.

Crew is not allowed to be on course for support. All support must be done within the village. You may stop and rest at any time along the course, but the race clock is still in motion. Athletes may not receive any assistance in the form of transportation. You may not have your support crew pace you during the run. You may, on your last run lap, invite your friends and family to run with you.


The ANVIL Village

Your Home Base During The Event. 

Each athlete will be assigned a "pit area" inside our ANVIL village. This pit area is where you will store belongings during the event and from where your crew will support you. The bike and run course go directly through the village every lap, giving you easy access to your supplies / food and crew. Our food tent, aid station and charging station are located directly in the middle of the village. The food tent is where athletes and crew can eat home cooked breakfast, lunch, dinner and a late night snack. Athletes have access to the food tent included with their registration. Crew must purchase food tickets in order to eat from our food tent during the race. The charging tent is to be used for charging phones, lights, etc... We do not provide phone cords but will have power strips available for you to plug in and charge your devices.

You may rent a tent space from Mammoth or bring your own 10x10 tent. You may bring your own chairs, coolers, food, equipment, etc.. We ask that there are no open flames inside your pit area. If bringing your own tent - you must have adequate weights to hold down the tent in case we experience any type of wind. Tent walls are also recommend to help protect you and your gear from the elements. We provide lights throughout the entire village area and will string blue or white LED top lights in your tent once you are setup and ready. You may also bring your own lights if you choose. 

Renting a tent space for Mammoth:
During registration, you'll have the choice to rent a shelter from us. This is a 10x8 space and includes one 8 ft table and two folding chairs. We have a limited supply of space available so please make sure you register early and add-on a shelter when registering.



Athletes have the ability to receive aid from their crew every lap of the ANVIL. This is one of the
many benefits of racing the ANVIL

We also make a point to keep our Aid Station full with both liquid and solid fueling options. Hammer Nutrition provides us with clean products that have been rigoursly tested to ensure quality and effectiveness for their athletes. We provide, free of charge, various Hammer products to all registered athletes. 

We highly recommend fueling with Hammer and using their product while training. All of their products are guaranteed to be free of any banned substances and help you reach your maximum potential as an athlete. They also provide fueling education in the form of videos, booklets and podcasts. There's a reason Hammer is trusted and used by some of the best athletes in a variety of different sports. Hammer on, friends. 

Our aid station will also serve as the "kitchen" area inside the village. This is where you and or your crew will stop to get breakfast, lunch, dinner and a late night snack. Our food is all home cooked with care and served timely to help you stick with your fueling plan and have a successful event. You can find our race menu in the Athlete Guide. Vegan / Gluten free options are available for every meal upon request.

Lastly, we will have water and RedBull products available throughout the entire event at the Aid Station.



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