Lou Dillon (1898, near Santa Ynez, California—January 15, 1925, near Santa Barbara, California) was a Standardbred trotting horse. She was the first trotter to trot a mile in under 2:00, which she completed at Memphis in 1903. Her owner was Henry Pierce, who never raced her professionally. She was trained initially by Charles Tanner, who drove her in many amateur events. Later her workouts under (1856-1928) were fast, and she attracted a lot of attention.