The Tunnel Hill 50 Mile, held in Vienna, Illinois, continues to be a race where world records fall, and on November 8, 2025, it was Anne Flower setting a new women’s 50-mile world record with a time of 5:18:57. Courtney Olsen held the previous record that she set when she ran 5:31:56 at Tunnel Hill just last year. Olsen raced the 100k event this year and received a mid-race 50-mile split of 5:33:59 as the second woman for the distance.
Anne Flower setting a new women’s 50-mile world record. Photo: Micki Colson/Colson Photography
Flower was able to maintain an average pace of 6:23 minutes per mile (3:57 minutes per kilometer) over the 50-mile course (80.47 kilometers) and never seemed to be in any difficulty, even as temperatures rose later in the race.
Flower, an emergency room doctor based out of Colorado Springs, Colorado, made headlines earlier this summer when she beat Anne Trason’s 31-year-old record at the 2025 Leadville 100 Mile at her first attempt at 100 miles. Before turning to trails in 2019, Flower had a history in marathons and competed in the 2020 U.S. Olympic Marathon Trials. In recent years, her focus has shifted more to trails. Flower talked extensively about her unique approach to running in an interview with iRunFar in September 2025. Leading up to her breakout run at Leadville, she’d won the 2025 Silver Rush 50 Mile, and she also won the Javelina 100k in the fall of 2024. The Leadville 100 Mile was a big step up in distance for Flower, who historically leaned toward 50k and 50-mile races in her ultrarunning, and her experience with the distance showed through at Tunnel Hill. From the start, Flower ran under world record splits at an incredibly consistent pace.
Anne Flower was all smiles after running incredibly consistent splits to a new women’s 50-mile world record. Photo: Micki Colson/Colson Photography
The Tunnel Hill 50 Mile is held on the Tunnel Hill State Trail, and the course sends racers on a double out-and-back on a flat course mostly made of a crushed gravel surface. The race gets its name from the tunnel racers pass through on the rails-to-trails trail. This is the third world record set on the course since 2023, when Charlie Lawrence set a new men’s 50-mile world record of 4:48:21. The course is certified by USA Track and Field (USATF), and the race is an International Association of Ultrarunners (IAU) Gold Label event. The race was also this year’s USATF 50-Mile National Championships. The 50-mile distance world record has been governed by the IAU since January 2022, and they will be responsible for certifying the world record.
