Complex sentence: Chincoteague Inlet, a break in the barrier island system, occurs near Chincoteague Island, at the southern end of Assateague Island, that shelters Chincoteague from the Atlantic and that stretches north almost thirty miles to Ocean City, Maryland.
Split into simpler sentences: Chincoteague Inlet, a break in the barrier island system, occurs near Chincoteague Island, at the southern end of Assateague Island. Assateague shelters Chincoteague from the Atlantic and stretches north almost thirty miles to Ocean City, Maryland.