Yes, a white horse has won the Kentucky Derby if you interpret white as 'roan' or 'gray'. According to those criteria, there have been eight [8] such winners:
1. Determine [1951 - 1972], gray stallion winner in 1954;
2. Decidedly [1962 - ?], gray stallion, in 1959;
3. Spectacular Bid [February 17, 1976 - June 9, 2003], gray stallion in 1978;
4. Gato Del Sol [February 23, 1979 - August 7, 2007], gray stallion, in 1982;
5. Winning Colors [February 14, 1985 - February 17, 2008], a filly that officially was described as a 'roan' but actually was soft gray with a white face, in 1988;
6. Silver Charm [foaled February 22, 1994], gray stallion, in 1997;
7. Monarchos [foaled 1998], gray stallion, in 2001; and
8. Giacomo [foaled February 16, 2002], gray stallion
It's a bit of a trick question, all horses in the Derby are 3 yrs of age and no more, no less. Female horeses aren't called mares until they reach age 5. So the short answer to the question is, "None."
There have been 3 female horses win the Derby however--referred to as a "filly"before age 5. They were: Winning Colors, Genuine Risk and Regret.
No because the Kentucky Derby is only for 3 year olds, so its a one time chance, you win or you don't
Giacomo won the Kentucky Derby in 2005.
Horse 'Secretariat' won the Derby in 1973.
A horse named Thunder Gulch won the Kentucky Derby in 1995.
Giacomo won the 2005 Kentucky Derby. He won with odds of 50-1.
The Kentucky Derby did not begin until 1875.
The 14th Kentucky Derby was run in 1888 and won by MacBeth II.
If you are talking about the Kentucky Derby, the horse was Jet Pilot.
A horse named Elwood won the thirtieth Kentucky Derby in 1904. Elwood was the first horse bred and owned by a woman to win the Derby.
Real Quiet won the '98 Derby.
Super Saver won the 2010 derby.
Horse 'Chateaugay' won the 1963 derby ridden by Braulio Baeza.
Aristides won the first Kentucky Derby back in 1875.