From the early 1700s, in the age of the sailing ships, to the onset of the Second World War in 1939, when the last transatlantic steamer sailed from the port, Londonderry was one of the principal emigration ports in Ireland.
Derry port possessed an ideal situation. She stood at the head of a virtually land-locked Lough Foyle, 24 miles long and only 2 miles wide at its head. The Lough was sheltered from the prevailing westerly winds by the Inishowen peninsula, thus making it, in the age of sail, a harbour of refuge, accessible and safe in all weathers. Owing to her westerly situation Derry was seen as being halfway between London and the American colonies; a Derry ship “is no sooner out of the river, but she is immediately in the open sea and has but one course”.

18th Century Emigration and the Scotch-Irish
Derry was, therefore, well placed to benefit from the widespread emigration of Ulster people to North America from the early 1700s. Between 1717 and the beginning of the War of American Independence in 1776, 250,000 Scotch-Irish or Scots-Irish – or Ulster-Scots as they are known in Northern Ireland (i.e. descendants of 17th century Scottish Presbyterian settlers in the 9 counties of the Province of Ulster: Antrim, Armagh, Down, Fermanagh, Londonderry, and Tyrone in Northern Ireland and Cavan, Donegal and Monaghan in the Republic of Ireland) – emigrated from Ireland through the ports of Belfast, Londonderry, Newry, Larne and Portrush for the British Colonies in North America.
Conditions on board 18th century emigrant ships were tough. Disease thrived on overcrowded ships, with all emigrants accommodated, in communal berths, in the space between decks – the height between decks seldom exceeded 5 feet 6 inches; four feet six inches was common. Port holes to provide ventilation and light were non-existent. Further hazards included storms, shipwreck and even capture by French and Spanish privateers. By the 1770s the voyage across the Atlantic, on average, took 7 weeks with the fastest being 27 days by Jupiter to Philadelphia from Derry in 1772 and the slowest being 17 weeks by General Wolfe also toPhiladelphia from Derry in the same year.