Trail running course through technical terrain in Illinois, USA
Shawnee Hills Trail Races

Shawnee Hills Trail Races — 100 Miles

100 Miles·5,512 ft gain·Ozark, Illinois
ultra100 mileforesttechnicaltrailloop

AI-generated image

Distance100 Miles
Gain5,512 ft
DateAug 22, 2026
Difficulty4/5

About This Race

The 100-mile distance represents the ultimate test of endurance and navigation through Shawnee's most demanding terrain. Runners face multiple loops that reveal different aspects of the forest throughout the day and night, with technical rock sections and root-laden trails requiring constant attention even as fatigue mounts. This is a race for experienced ultra runners seeking a challenging but achievable century finish in the Midwest.

The course follows a figure-eight loop design through the sandstone canyons of Shawnee National Forest, with 80% singletrack trail and connecting fire roads. Technical terrain dominates, featuring rocks, roots, creek crossings, and persistent elevation changes that range from 50 to 150 feet per segment. The route traverses Jackson Hollow and skirts Bay Creek Reservoir while linking multiple waterfall systems including Jackson Falls, Horseshoe Falls, and Cedar Falls, culminating at Pakentuck Falls.

Distance variations use different combinations of the loop system: the 100-mile starts with a short 3-mile section followed by three 32-mile loops, while the 100K covers two full loops, the 50K runs one complete loop, and the half marathon follows the western section. Scenic highlights include views from Salomon's Ridge and passage through the diverse forest ecosystems that characterize the region.

Elevation Profile

Elevation profile estimated from terrain data. Actual course may differ.

The course gains 5,512 ft over 100 miles, with the steepest section between mile 52–mile 52.

Location

Practical Info

Weather

August conditions typically bring high heat and humidity, with temperatures potentially reaching the 80s-90s Fahrenheit and significant humidity levels typical of the Midwest summer.

Accommodation

Camp Ondessonk offers unique lodging including rustic treehouses (open-air sleeping with roof coverage), traditional camping areas, and limited climate-controlled hostel-style rooms with private bathrooms that sleep 8 people.

Best For

Experienced trail runnersUltra runners seeking technical terrainRunners comfortable with wilderness conditions

Notable Features

The race stands out for its access to Illinois' most spectacular waterfall collection, including the state's tallest free-falling waterfall at Pakentuck Falls. The unique accommodation options at Camp Ondessonk, particularly the open-air treehouses, create an immersive weekend experience that combines serious trail running with rustic outdoor lodging in one of the Midwest's most pristine wilderness areas.

Other Distances at This Event

Half Marathon

2,001 ft gain

The course follows a figure-eight loop design through the sandstone canyons of Shawnee National Forest, with 80% singletrack trail and connecting fire roads. Technical terrain dominates, featuring rocks, roots, creek crossings, and persistent elevation changes that range from 50 to 150 feet per segment. The route traverses Jackson Hollow and skirts Bay Creek Reservoir while linking multiple waterfall systems including Jackson Falls, Horseshoe Falls, and Cedar Falls, culminating at Pakentuck Falls. Distance variations use different combinations of the loop system: the 100-mile starts with a short 3-mile section followed by three 32-mile loops, while the 100K covers two full loops, the 50K runs one complete loop, and the half marathon follows the western section. Scenic highlights include views from Salomon's Ridge and passage through the diverse forest ecosystems that characterize the region.

50K

4,524 ft gain

The course follows a figure-eight loop design through the sandstone canyons of Shawnee National Forest, with 80% singletrack trail and connecting fire roads. Technical terrain dominates, featuring rocks, roots, creek crossings, and persistent elevation changes that range from 50 to 150 feet per segment. The route traverses Jackson Hollow and skirts Bay Creek Reservoir while linking multiple waterfall systems including Jackson Falls, Horseshoe Falls, and Cedar Falls, culminating at Pakentuck Falls. Distance variations use different combinations of the loop system: the 100-mile starts with a short 3-mile section followed by three 32-mile loops, while the 100K covers two full loops, the 50K runs one complete loop, and the half marathon follows the western section. Scenic highlights include views from Salomon's Ridge and passage through the diverse forest ecosystems that characterize the region.

100K

377 ft gain

The course follows a figure-eight loop design through the sandstone canyons of Shawnee National Forest, with 80% singletrack trail and connecting fire roads. Technical terrain dominates, featuring rocks, roots, creek crossings, and persistent elevation changes that range from 50 to 150 feet per segment. The route traverses Jackson Hollow and skirts Bay Creek Reservoir while linking multiple waterfall systems including Jackson Falls, Horseshoe Falls, and Cedar Falls, culminating at Pakentuck Falls. Distance variations use different combinations of the loop system: the 100-mile starts with a short 3-mile section followed by three 32-mile loops, while the 100K covers two full loops, the 50K runs one complete loop, and the half marathon follows the western section. Scenic highlights include views from Salomon's Ridge and passage through the diverse forest ecosystems that characterize the region.