"The Population of the United States, 1790-1920"
In the 130 years from the first federal census of the United States in 1790, the American population increased from about 4 million men to almost 107 million persons. This was predominantly due to natural increase, early driven by high birth rates and moderate motrality levels and after the Civil War by declining death rates. In addition, over 33 million recorded immigrant arrivals increased the growth rate. By the two decades prior to World War I, about one third of total increase originated in net migration. A number of unusual features characterized the American demographic transition over the `long' nineteenth century. The fertility transition was early (dating from at least 1800) and from very high levels. The average woman had over seven livebirths in 1800. The crude birth rate declined from about 55 in 1800 to about 25 in 1920. This occurred before 1860 in an environment without widespread urbanization and industrialization in most of the nation. Mortality levels were moderate, and death rates began their sustained decline only by the 1870s, long after the fertility transition had begun. This constrast to the more usual stylization of the demographic transition in which mortality decline precedes or accompanies the fertility transition. Internal migration in the United States was also distinctive. Over most of the 19th century flows followed east-west axes although this began to weaken as rural-urban migration began to supplant westward rural migration in importance. International migra- tion proceeded in waves and changed its character as the `new' migration from eastern and southern Europe replaced `old' migration from western and northern Europe.
S. Engerman and R. Gallman (eds.) The Cambridge Economic History of the United States, Vol. 2. Cambridge, UK: Cambridge University Press, 2000.