Misty of Chincoteague, by Margeurite HenryRead about the other books on the list.
Paul and Maureen are a brother and sister who love horses, and long for one of their own. Will they be able to save up enough money to buy wild mare Phantom and her foal, Misty, who have captured their hearts? Based on the story of a real life wild pony who was raised in captivity by the Beebe family of Chincoteague Island, Virginia, every child who reads this story will dream of visiting Chincoteague—which I can say from experience will NOT disappoint. Plus, it’s cheaper than Disneyland. Family road trip!
Also see Belinda Rapley's top ten horse books and Megan Wasson's eight great books about horses.