The long-distance triathlon with a swim, bike ride, and full marathon run is branded as the Ironman. The classic Ironman distance combines a 3.8-kilometre swim, a 180-kilometre bicycle ride, and a 42.2-kilometre marathon. Distances are sometimes rounded in descriptions to 3.9 kilometres and 180 kilometres.
The first Ironman was held in Honolulu, Hawaii, in 1978, after organizers combined several existing endurance races into one event. Gordon Haller became the first winner, completing the course in 11 hours, 46 minutes, and 58 seconds. The competition later moved to Kailua-Kona, where the Ironman World Championship became one of endurance sport's best-known events.
Ironman is a brand name, not simply a generic synonym for every long triathlon. The related Ironman 70.3 race uses approximately half the full-distance course: a 1.9-kilometre swim, 90-kilometre bike ride, and half marathon. Ultraman is a separate ultra-endurance event with different rules and distances, so it is not the answer to this question.