WASHINGTON (AP) _ President Clinton will travel Friday to the barrier island famous for an annual roundup and sale of wild horses, the White House said Wednesday.

Clinton is expected to highlight environmental threats at Assateague Island, home to bands of wild ponies that roam the scrubby beaches of a national wildlife and marine preserve.

In a tradition dating back a century, wild ponies annually swim the channel between Assateague and Chincoteague islands off the Maryland-Virginia coast. Some are then auctioned in the town of Chincoteague, Va., as a local fund-raiser.

Many tourists are drawn to the event due to its mention in the 1947 novel ``Misty of Chincoteague,'' by Marguerite Henry. The children's book tells the story of a brother and sister who want to own a wild pony and her filly.