CORRECT answer is 26 miles 385 yards. In 1921 the LENGTH for a marathon was formally standardized at 26.2 miles (42.195 KILOMETERS). Marathon:The marathon is a long-distance race with an official distance of 42.195 kilometres, usually run as a road race.The history of marathon race began in 490 BC.There was a war going on between the Greek and Persian soldiers on the grounds of marathon, 26 miles away from ATHENS.In the battle of Marathon, around 10 thousand Greek soldiers DEFEATED one million Persian soldiers and protected their homeland.The Greek soldier "Pheidippides" run around 26 miles from Battle of Marathon to Athens, to report the victory of his country in the war without stopping in the way.