The nineteenth century was without doubt the most significant century in terms of establishing the Irish diaspora. The dominance of North America as the favoured destination for Irish migrants was enhanced with a staggering 5 million emigrants crossing the Atlantic between 1800 and 1900. British North America, what would later become Canada, was a significant place of settlement in the first half of the century with 2 out of every 5 Irish trans-Atlantic emigrants in the pre-Famine era settling north of the 49th parallel. This represents a total of about 400,000 emigrants. Britain, by some distance was the second most important destination for nineteenth century emigrants. Estimating the volume of this flow is severely hampered by the absence of any systematic recording of movement across the Irish Sea. The fact that many migrants spent time in Britain prior to departure for New World destinations or moved on a seasonal basis adds to the statistical conundrum. Nonetheless, throughout the course of the nineteenth century it is probable that somewhere in the region of 1.5 million migrants crossed from Ireland to Britain. Britainís colonies also absorbed a smaller proportion of Irish emigrants. Over the course of the century Australia received an estimated 350,000 Irish, New Zealand about 80,000 and South Africa no more than 15,000. Argentina, which in terms of mercantile trade could be thought of as a quasi-British colony, acted as a destination about 30,000 Irish emigrants. The massive scale of Irish emigration between these dates becomes clearer when, on the basis of an 1841 population of 8,175,124 and a total of 6,975,000 emigrants, we calculate an emigration rate of 85.3%. Two interesting features of this exodus become apparent when set into the wider European context. In Ireland the gender profile of emigration was more evenly balanced than was the case in most other European countries, where male departures predominated. It was also the case that a relatively small proportion of the emigrants who left Ireland for New World destinations returned (approximately 1 in 10) as compared to a European average of about 3 in 10.