The unequal distribution of public costs and the neglect of social questions drove many tradesmen, day labourers and small farmers to ruin. As a result, from the thirties there was a massive wave of emigration to the United States. Inspired by the Solingen doctor Gottfried Duden, who as an academic had vainly tried for several years to run a farm in Missouri, and had published his experiences in book form, at the beginning of the thirties the "Solingen Society of Emigrants" left their native country. These people acted as a bridgehead and were the cause of the mass emigration of about 250,000 Rhinelander, who followed their call to the New World.
While in principle Prussia had no longer restricted the freedom of movement of its citizens since 1818, permission to emigrate was linked to the approval of regional administrations, of active civil servants of the responsible authorities and military obligations. The first legal regulation of emigration from Prussia was effected in 1842. Statistics about emigration were kept from 1st October 1844, but did not include all illegal emigrants, without discharge papers, until 1855. From 1844 till 1871, 125,648 inhabitants of the Rhine Province were recorded as emigrants, until 1852 with the inclusion of Hohenzollern-Sigmaringen, which was assigned to this province for administrative purposes. Relatively few Rhenish emigrants went to the USA. According to an American census from 1870, merely 5,330 (0,32%) of about 1.6 million German immigrants in the U.S.A. gave the Prussian Rhine Province as their region of origin in Germany.
The five Rhenish administrative regions in Prussia showed varying willingness to emigrate, whereby the rates of emigration were much higher in the structurally weak areas of the Eifel, Hunsrück and Westerwald than in the rapidly industrialized northern half of the Rhine Province, which also had the advantage of better infrastructure. From 1844 till 1871 the administrative regions of Düsseldorf (17.205/1.6%), Cologne (11.075/2.1 %), Aachen (8.926/2.0%), Trier (50.254/9.4%) and Koblenz (38.188/ 7.35%) lost one in 25 inhabitants, on average (4.0% of their population) to emigration to other states of the German Federation, Europe and America.
From the numerous letters received from emigrants, it emerges just how selectively farmers and tradesmen were recruited by those who had gone ahead of them. Very soon the Prussian government found itself forced to regulate emigration, in order to keep qualified tradesmen bound to the Rhineland. After the introduction of the Emigration Agreement, thousands of Rhinelanders left their native country without permission, in order to settle in America, among them were countless deserters.
Until the seventies the Rhine was the most important waterway for those willing to emigrate. Some migrants travelled as far as Rotterdam on rafts. On the other hand, in the second half of the 19th century, those on higher incomes could afford to travel on the Cologne-Minden railway. The last stretch was then covered by barge down the river Weser to Bremerhaven, the most important German port of departure for emigrants.