Ships plied the Atlantic bringing flax seed from America to the Ulster domestic linen industry in the eighteenth century and the empty cargo ships carried many emigrants on the return journey.
The 'push' factors were religious tensions and economic uncertainty in Ireland.
The 'pull' factors were cheap land and the prospect of a better lifestyle promoted by sailors and contacts in America.
When a high proportion of women went along, emigrants tended to settle in family groups and retain their native identity, at least for a few generations. In some colonies women enjoyed more favourable legal rights to property and custody of their children than under English law in Ireland.