Due to its natural shelter and its depth, the lough was an important naval port. In October 1798, immediately prior to the outbreak of the Napoleonic wars, a French fleet carrying Wolfe Tone of the United Irishmen, plus troops to assist in 1798 rebellion, was intercepted and defeated in a naval battle at the entrance to Lough Swilly. Subsequently Tone was captured and taken ashore at Buncrana on the east side of the Swilly.