German transatlantic mass emigration was above all a phenomenon of the 19th century. Around 90 % of the Germans headed for the United States. While from 1820 to 1960 around 6.7 million left for the North American republic, around 5 million went there from 1820 to 1900 alone. Thus along with the British and the Irish the Germans were the most important immigrant group to settle in the New World.

Some left for religious and others for political motives. But the most important reason for this mass exodus was certainly the steadily deteriorating economic and social condition of large sections of the German population from the beginning of the 19th century. As a consequence of industrialization, modernization and the dissolution of traditional agrarian and urban structures the population grew rapidly while the supply of employment did not keep pace with this population explosion.