Marguarite Henry's story of Misty of Chincoteague was one of the earliest influences on my love of horses. The book was written in 1947 about a wild pony on Chincoteague Island off the east coast of the USA and followed up by two sequels. I read the books as a child and a lifelong ambition to visit and photograph the ponies was fulfilled in 2008.
The wild ponies aren't actually, we discovered, on Chincoteague at all. They inhabit the vast and wild Assateague Island, now protected as the Assateague National Seashore. The long stretch of Assateague is in two states, Virginia and Maryland and the ponies are managed very differently in each, with the Virginia ponies free to roam and interact with visitors, often leading to conflicts over damage to tents and raiding picnics, while the Virginia ones are separated by a fence and seem to lead a wilder and more untouched life.
Each year ponies in both areas are rounded up, swum across to neighbouring Chincoteague and youngstock are sold at an annual fair with the proceeds from the sale supporting the island's fire service. I haven't yet managed to photograph the 'pony swim' but hope to be back and tell that story another day.