The Grand Slam of Ultrarunning Series returns to Kaysville, Utah on September 11th, bringing together endurance runners from across the country for a challenging set of races that trace back to the origins of ultramarathon running in America. The series comprises five rigorous 100-mile trail runs: Old Dominion Endurance Run, Western States Endurance Run, Vermont 100 Endurance Race, Leadville Trail 100 Run, and Wasatch Front 100 Mile Endurance Run. Each race is steeped in history and tradition, with the Grand Slam of Ultrarunning Award presented to those who complete three out of the original four races followed by the Wasatch Front 100 Mile Endurance Run within a single summer. Runners will face varied terrain throughout each course, ranging from hilly trails to rugged mountains. The races traverse through diverse landscapes in Utah and other states, offering both scenic beauty and challenging conditions that test runners' endurance limits. Kaysville, known for its serene surroundings and picturesque scenery, provides an ideal setting for the final race of the series. On early September mornings, temperatures are mild with firm trail conditions making it suitable yet demanding. Since 1985, this event has celebrated ultrarunning excellence by honoring runners who have demonstrated exceptional commitment and skill over multiple races across different terrains. The Wasatch Front 100 Mile Endurance Run acts as the concluding race of the Grand Slam Series, celebrating participants at its awards ceremony with a rich history dating back to when Tom Green was awarded the inaugural prize in 1986. The course for each event is meticulously planned to challenge runners physically and mentally. The Wasatch Front route winds through diverse landscapes around Kaysville, featuring varied elevations that make it especially testing. Aid stations are strategically placed along the trail to provide essential support throughout the race day. Runners can expect moderate UV exposure during their early morning start times. Trail conditions will be firm but slightly soft underfoot, ensuring a tough yet manageable surface for endurance runners. The weather in Kaysville in September tends towards mild temperatures with little precipitation risk; however, participants should prepare for variable daytime and nighttime temperatures as the race progresses over multiple days. The Grand Slam of Ultrarunning Series offers an unparalleled challenge through its various 100-mile trail runs across different states leading up to the final event in Kaysville. Participants must apply specifically for the Wasatch Front Endurance Run during a designated period from December 1st until January 4th, with no late applications accepted. Registration can be completed at [https://ultrasignup.com/register.aspx?did=133075](https://ultrasignup.com/register.aspx?did=133075). The fee for the Grand Slam of Ultrarunning Series is set at $105. Bib pickup will occur on-site in Kaysville, Utah from September 8th to 9th where participants must bring valid identification and proof of participation in previous races. The start location is accessible via detailed directions provided by race organizers. Runners should be aware that age requirements apply for each individual event within the series; specific details can usually be found on the registration page or at bib pickup locations. For first-timers, ensuring proper footwear suitable for trail conditions and bringing a hydration pack are essential preparations. The Grand Slam of Ultrarunning Series in Kaysville, Utah offers a compelling challenge to endurance runners looking to test their limits across some of America's oldest ultramarathon trails on September 11th. Runners from around the United States gather here not just for competition but also as part of a broader celebration of running culture and community spirit.
Grand Slam Start: 05:00:00 • Fee: $105.00
Races Offered
Grand Slam
Sep 11, 2026
straighten
Distance —
160.9K
terrain
Type —
Running
timer
05:00
sell
$105.00
Weather History
These values represent the 3-year monthly averages for September in Kaysville.
thermostatTemperature
13.6° / 26.6°
wb_sunnyFeels like
11.1° / 23.4°
light_mode
Avg sunshine hours
11h 32m
water_drop
Avg rainfall
0.7 mm
ac_unit
Avg snowfall
—
air
Avg wind speed
7.9 km/h (Light breeze)
opacity
Sweat loss rate
Moderate
terrain
Course conditions
Hard and dry surface
sunny
Max UV Index
Moderate (5.0)
humidity_mid
Humidity
40.1%
wb_twilight
Sunrise
07:09
nightlight
Sunset
19:35
About Kaysville
Learn more about the host city, Kaysville.
Kaysville is a city in Davis County, Utah. It is part of the Ogden–Clearfield metropolitan area. The population was 32,945 at the time of the 2020 census.