John and Susan Dean lived in Northern Ireland from 1790-1795. They left because of the political situation. If you think the troubles then were the same as the Irish troubles of recent years, you would be surprised to know the truth.
Instead of Irish Catholics versus Irish Protestants in Ulster, there was a group called the Society of United Irishmen, who were united against the English. At that time only those who were Church of England, the state church, were allowed to vote, hold office, own land, and a host of other privileges. So Irish Protestants in the north, being mainly Presbyterians, were excluded too. The purpose of the United Irishmen was to break the connection with England and establish an Irish Republic.
The American Revolution had recently succeeded and the French Revolution was in full swing at this time. There was a revolutionary republican zeal among the Irish. Every year on July 14th, there was a great procession in Belfast to celebrate the anniversary of the Fall of the Bastille. In 1791 a speech was made congratulating the fact that “in the Christian world one great nation had renounced all idea of conquest.”
In 1793, with the declaration of war against the French, Britain instigated harsh measures against the popular Republican cause in Ireland. Such measures only heightened Irish hatred of the English. The Deans, especially Susan who was English, could not have been comfortable in Ulster, and so they emigrated to America in 1795.