Thornfield (foaled 1994 in Ontario) is a Canadian Thoroughbred Champion racehorse.
Thornfield was bred by Steve Stavro's Knob Hill Farm, he was sired by Eclipse and Sovereign Award and Canadian Horse Racing Hall of Fame inductee Sky Classic, a son of the English Triple Crown winner, Nijinsky.
Thornfield's dam was Alexandrina, a daughter of 1982 American Horse of the Year, Conquistador Cielo.
In 1999, under trainer Phil England, five-year-old Thornfield won the Grade 2 Niagara Breeders' Cup Handicap.
Ridden by Richard Dos Ramos, they then won the $1.5 million Canadian International as the longest shot in the field.