The English Grand National, not a flat race but it's run in the flat season, making it the longest race in the flat race season.
Indy 500
Surely the grand national - jumps (4M 4F) Possibly the ascot stakes - flat (2M 6F) The longest flat race under Jockey Club Rules is The Newmarket Town plate at 3M 6F. The Grand National is run under National Hunt Rules.
The longest race is the 50 Km walk. The longest running race is the Marathon.
The Coca-Cola 600 is currently the longest sanctioned Nascar race.
the longest note is the flat note
The Great Serum Race
The Self-Transcendence 3100 mile race is the world's longest certified footrace according to its organizers.
The MarathonThe longest running race is the marathon at 42.195KM (26miles 385yards)The longest foot race is the mens 50K walkThe longest race is the triathalon - 1500M swim + 40KM cycle + 10KM run
over 60 miles is germanys longest racing track or the longest track in the world
The longest race of the Triple Crown is the Belmont Stakes run at 1 1/2 miles (12 furlongs).
Champion Standard Open NH Flat Race was created in 1987.