Lough Swilly () in Ireland is a glacial fjord or sea inlet lying between the western side of the Inishowen Peninsula and the Fanad Peninsula, in County Donegal. Along with Carlingford Lough and Killary Harbour it is one of three glacial fjords in Ireland. Geography and ecology Located on the Fanad Peninsula, in County Donegal, the northern extremities of the lough are marked by Fanad Head with its lighthouse and Dunaff Head. Towns situated on the lough include Buncrana on Inishowen and Rathmullan on the western side. At the southern end of the lough lies Letterkenny. In the south of the lough a number of islands (Burt, Inch, Coney, Big Isle) were poldered and the land reclaimed during the 19th century for agriculture and the Londonderry and Lough Swilly Railway constructed embankments on the line from Derry to Letterkenny. These reclaimed lands are now wetlands associated with wildlife conservation and birdwatching, and support over 4,000 whooper swans and thousands of Greenland white front, barnacle, greylag and brent geese. The lough is known for its wildlife-watching (dolphins, porpoise, seabirds, migratory geese and swans) and diving on a number of ship wrecks, including sunk by a German mine (possible torpedo), which went down with 3,211 ingots of gold of which 3,191 were recovered. History The lough, and the Grianán Ailigh hill fort (early fortification and palace dating from 2000–5000 BC) at its southeastern bend, were recorded on Ptolemy's map of the world. It has a number of early Stone Age monuments and Iron Age fortifications along its shores, as well as a number of shell middens dated to approximately 7000 BC. Swilly was the departure point for the 'Flight of the Earls' in 1607. This event, which followed a failed uprising in September 1607, saw Hugh O'Neill, 2nd Earl of Tyrone, and Rory O'Donnell, 1st Earl of Tyrconnell (the last Gaelic chieftains in Ireland at that time), set sail from Rathmullan with ninety of their followers. During a gale on 4 December 1811, the Royal Navy 36-gun was shipwrecked in Lough Swilly. There were no survivors out of the estimated 253 aboard, with approximately 200 bodies washed up on shore. 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