Populations caused changes in social systems

Coping with the rising tide of European immigration
http://memory.loc.gov/cgi-bin/query/r?ammem/gmd:@field(NUMBER+@band(g5701e+ct002765))

Rand, McNally & Co.'s map of the United States showing, in six degrees the density of
population, 1890.
http://memory.loc.gov/cgi-bin/query/r?ammem/gmd:@field(NUMBER+@band(g3701e+mf000043))

Statistical map of the United States of America Prepared by James S. Cowdon and James D. Holman, Special Statisticians, under the direction of the Hon. John C. Black, Commissioner of Pensions.
http://memory.loc.gov/cgi-bin/query/r?ammem/gmd:@field(NUMBER+@band(g3701s+cw0062600))

Map showing the distribution of the slave population of the southern states of the United States. Compiled from the census of 1860 Drawn by E. Hergesheimer. Engr. by Th. Leonhardt.
http://memory.loc.gov/cgi-bin/query/r?ammem/gmd:@field(NUMBER+@band(g3861e+cw0013200))