Sadly, Fort Niagara is not 100% circumnavigable...because US Coast Guard Station Niagara is in the way. Whenever my way is checked by a Coast Guard Station when I'm visiting a starfort (which has really only happened on a few occasions), it reminds me that the folks who sited that starfort centuries ago did so with eminent wisdom, as the spot they chose is still important in the 21st century. Way to go, Frenchmen.