Ultrarunning is a sport where competitors run footraces longer than the 42 km 195 m (26.219 miles) required by the Marathon. The events are also known as ultramarathons.

Typical ultrarunning events are 50 and 100 kilometres, or 50 and 100 miles, depending upon the conventions of the country in which they are held. Of course, multiples of these decimal numbers may be run, all of the above distances come under the term ultramarathon. A non-decimal ultrarunning distance is the double-marathon (52 miles/84 kilometres).

On July 22, 2003, Pam Reed, 42-year-old mother of five, won the Badwater Ultramarathon through Death Valley, California, completing the 135-mile course in 27 hours, 56 minutes. Temperatures reached 133 °F. The fact that Reed beat a 73-person international field of men and women by nearly five hours lead some to believe that women are better suited than men for such severe endurance competitions.