An ultramarathon is any running race longer than a traditional marathon (26.2 miles). Most ultramarathons are either 50 kilometers (about 31 miles) or 50 miles, though some stretch to 100 miles or even longer. Some ultramarathons last for a set time, like 24 hours, where runners see how far they can go before time runs out.

These races often take place on challenging terrain like mountain trails, deserts, or through forests, rather than on smooth city streets. Runners might climb steep hills, cross streams, and navigate rocky paths in all kinds of weather. The Western States 100, one of the most famous ultramarathons, crosses the Sierra Nevada Mountains in California.

Ultramarathon runners need extraordinary endurance and mental toughness. Unlike a regular marathon that might take three or four hours, an ultramarathon can take anywhere from seven hours to two full days. Runners must eat and drink during the race to keep their energy up, and many have support crews who meet them at checkpoints along the course.

An ultramarathon goes beyond what most people would consider a normal running distance. While finishing any marathon is impressive, completing an ultramarathon represents an exceptional level of determination and physical conditioning.