"Most portraits of George Washington show him majestically mounted on a brilliant white charger. But in fact, Washington's favorite mount was a chestnut hunter named Nelson who was a gift from the Governor of Virginia, Thomas Nelson, Jr. Washington rode Nelson to fox hunts for ten years before the Revolution and took his horse with him on his many campaigns during the war. Some of General Washington's other mounts died from exhaustion carrying him through furious battles. But Nelson survived the rigors of near-starvation at Valley Forge and relentless marches from Boston to the Carolinas. During Washington's term as first U.S. President, Nelson remained his favored horse. He too remained "first in war, first in peace..." - if not first in the memory of history."
Link for above:
http://www.imh.org/imh/kyhpl3b.html