The Book of Extremes (Das Buch der Extreme, available at Amazon - German only), highlights the longest certified road race in the world, the Self-Transcendence 3,100 Mile Race, held annually in Queens, New York.
"Self-Transcendence 3100 Mile Race: Kings of Queens. 3100 miles equal 4989 kilometers. The participants in the annual Self-Transcendence 3100 mile race cover this distance, a little more than the distance from Lisbon to Moscow, in maximum 52 days. At least the course is not particularly difficult, no mountains are in the way of the runners.The course is flat for the whole distance and because the race is being held on a loop, the runners have run 5649 laps." (translated from the book).
Cross-posted from us.srichinmoyraces.org