U.S. Census Office, Distribution of the Population of the United States in 1890 (1898)

In the 1890 U.S. Census, Superintendent Robert P. Porter declared the official closing of the American Frontier, arguing that the "frontier line" separating settled from unsettled areas of the country no longer existed. This map of the distribution of the population in 1890 was featured in the 1898 Statistical Atlas of the United States, Based Upon the Results of the Eleventh Census, as part of a series of maps showing changes in the population distribution from 1790 to 1890. Henry Gannett, who authored the Atlas, wrote of the map, "In 1890, which closes this series, the progress of settlements is seen to have been at least equally rapid with that of the decade before. Settlements in the Rocky Mountains had increased enormously and had joined with those moving up the plains, forming a continuous body of settlement. Those of Montana, Washington, Oregon, California, and Utah had spread until throughout this region the settled area has become the rule and the unsettled area the exception." Echoing Porter, Gannett then proclaimed, "There is no longer any frontier line" (p. 14).