The sport of running 100 miles competitively has existed for multiple centuries. The earliest known competition was won in 1792 by John Hague of Great Britain with a time of 23:15. In 1882, an American, John Hughes, reached 100 miles in 13:57 but was suspected as being drugged up with stimulants. John Dobler of the United States probably ran the fastest legitimate 100 mile time by an American in the 19th century when in 1880 he ran in London and reached 100 miles in 14:52.

But through the years before 1980, no one ran dozens of 100-milers during their running career, only a handful of 100s. Ultrarunning legend Ted Corbitt ran fewer than ten 100-milers. By the mid-1970s, running 100 miles in competition started to become more available to anyone. By 1978 there were seven races in American where runners could reach 100 miles. During 1981 about 250 runners finished 100 miles in races in North America. In 1990 that had doubled to about 500 runners.

By the end of 1999 as few prolific ultrarunners had piled up 100-mile finishes. Richard and Sandra Brown of England were way out in front with 87 and 82, reaching 100 miles in both running and walking events. Ray Krolewicz of South Carolina was next with about 60 100-mile finishes to his name. Don Choi, the prolific multi-day runner from San Francisco, had more than 40 100-mile finishes but had retired from 100-mile running in 1997 at the age of 48. The world's greatest, Yiannis Kouros had an estimated 40 100-milers, most of them wins and Tom Possert had about 30 100-milers. But as the decades passed, at the end of 2018, there were 15 talented ultrarunners who had achieved 100 100 milers.  Who are they?