Tunnel Hill 100

Tunnel Hill runs out and back along the Tunnel Hill State Trail, a converted rail corridor through the Shawnee National Forest in southern Illinois. The race describes the surface as flat, fast crushed limestone with a maximum grade of 2 percent, and the elevation stays between 340 and 680 feet the whole way: about 1,800 feet of climbing over 100 miles, and roughly 900 over 50. All distances leave Vienna City Park together at 7:00 a.m., and everything closes at 1:00 p.m. the next day.

The flatness is the point. The race calls itself the world's premier speed course and counts five world records set on it, among them Charlie Lawrence's 4:48:21 at 50 miles in 2023 and Caitriona Jennings' 12:37:04 at 100 miles in 2025. The 2026 edition hosts the USATF 50 Mile Championships, which pay $1,500, $750 and $500 to the top three men and women in the championship division.

An out-and-back on the Tunnel Hill State Trail from Vienna City Park, with aid roughly every five miles and a 543-foot limestone tunnel on the route. The race states a maximum grade of 2 percent and no altitude to speak of, with elevation between 340 and 680 feet. The 100 mile, 100 km and 50 mile all start together at 7:00 a.m. and share a hard course closure at 1:00 p.m. on Sunday, 30 hours later. Runners in the 100 mile must be on their second 50 within 15 hours, and the second half of that course carries aid-station cutoffs.

Entry is first-come on UltraSignup with no lottery and no qualifying standard, and closes October 30. The total field is capped, so the race deliberately limits the 100 km and marathon fields and those sell out first; runners entered in the 100 mile are allowed to drop down. The USATF 50 Mile Championship is a separate, cheaper entry, open to USATF members in good standing who are United States citizens.