The rate of urban growth in the United States reached its highestlevel in the twenty years before 1861. Nevertheless in the five preceding decades, 1790 to 1840, those coming just before the railroad age, the cities of the nation grew at a remarkably rapid rate. It is true that during one 10-year period of relatively slow growth, 1810–1820, the city population increased at a pace slightly below that for the total population. But in the other four decades, 1790–1800, 1800–1810, 1820–1830, and 1830–1840, the rate of increase in the number of people living in cities was almost double that for the whole population and exceeded the urban growth rate attained in any post-Civil War decade. This study makes available detailed statistics on urban population changes from 1775 to 1840, directs attention to the differing contributions to urbanization made by four city groups, and notes some of the influences affecting urban population expansion in the years before the railroad became a dominant influence.