This would depend on the distance. The most famous fastest horse would be Secretariat, but he was fast running distances over a mile. There are some horses known as sprinters who are very fast going short distances of a half-mile or 5/8ths of a mile. There is a great game, the best of all horse racing games I've ever seen, that let's you match up thoroughbreds from today and champion horses from yesterday and watch them race in 3D at various distances - http://www.horseracegame.com. Not only is this a great horse racing game, but it also lets you live out what might have happened when other champion horses meet. One final thing, according to several major sources, Groovy is considered the fastest race horse of all time. That's comparing him to such greats as Dr. Fager, Tom Fool and even Forego.
I believe the Fastest thoroughbred to be one that I most recently trained and she broke the track record for 2 furlongs at Penn National race course in Grantville, Pa. last May 2008. She traveled 2 furlongs in 20.2 to win the race and break the record that had been held there for years by a colt. So I believe the fastest thoroughbred filly is Winning Brew, unless somebody else can show me otherwise.
Come on everbody knows Rachel alexandra is the fastest horse to ever run. she just ran a mile and a eigth in 1:47 1/5 for fun! for crying out loud. she went 3/4 in 109 4/5 a mile in 134 flat. what else do you want??
RUFFIAN kicked the stud with the huge hearts times at all distances!
The fastest thoughrobred ever was Simply Majestic. He holds the world record for a mile and and eighth a t 1:45 flat. He took that record away from Secretariat and has held it for over 20 years. Today's horses don't even come close, with times in the 1:47 to 1:48 range being among the best.
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