American Quarter are the fastest horse in the World over short distances. They are able to run a quarter of a mile faster than any horse. Quarter, breed of light horse developed in the U.S. was by far the most popular cattle horse in the early West. The modern Quarter Horse has a small head with a straight profile, and a strong, muscled body. The American Quarter Horse is a breed of horse originally bred for sprinting short distances. Quarter is the most popular breed in the U.S. today as a race horse, show horse, working ranch horse and family horse. They come in nearly all colors. Quarter Horse can reach 55 mph (88 km/h) for a 1/4 mile.
Thoroughbreds are the fastest horses over long distances. They can keep 40 mph (64.3km/h) for a mile. Various types of horse breed developed for specific distances. According to Guinness - The highest race speed recorded over two furlongs is 43.97 mph (70.76 km/h) and was achieved by Winning Brew (trained by Francis Vitale for three months before the horse burst onto the scene), at the Penn National Race Course, Grantville, Pennsylvania, on 14 May 2008.
One of the most famous and fastest horses in the history of racing is a Secretariat, who competed from 1972 until 1973. He was a Triple-Crown Winner, and set race records that still stand today. Secretariat was an American Thoroughbred.