The American Champion Two-Year-Old Filly is an American Thoroughbred horse racing honor awarded annually to a female horse in Thoroughbred flat racing. It became part of the Eclipse Awards program in 1971.The award originated in 1936 when both the Daily Racing Form (DRF) and Turf and Sports Digest (TSD) magazine began naming an annual champion. Starting in 1950, the Thoroughbred Racing Associations (TRA) began naming its own champion.