What is the official distance of the Olympic marathon in track and field?

The official distance of the Olympic marathon in track and field is 42.195 kilometres.

This equals 26 miles and 385 yards. The distance was standardized after the 1908 London Olympics, where the marathon course ran from Windsor Castle to the finish in front of the royal box at White City Stadium. Earlier Olympic marathons had varied slightly in length.

The 1908 course measured 26 miles before an additional 385 yards were added so the race could begin at Windsor Castle and finish directly before the royal family’s viewing area. The distance was later adopted as the standard marathon length by international athletics authorities. Olympic marathons are held on roads rather than inside the athletics stadium, although the finish is traditionally near or inside the main venue.

The marathon is named after Marathon, the Greek town associated with the ancient Greek-Persian conflict. The modern event was introduced at the first modern Olympics in Athens in 1896, but its exact distance was not fixed at that time.