United States Census, 1840

The 1840 United States census was the sixth census of the United States. Conducted by U.S. marshals on June 1, 1840, it determined the resident population of the United States to be 17,069,453 – an increase of 32.7 percent over the 12,866,020 persons enumerated during the 1830 census. The total population included 2,487,355 slaves. In 1840, the center of population was about 260 miles (418 km) west of Washington, D.C., near Weston, Virginia (now in West Virginia). This was the first census in which: A state recorded a population of over two million (New York) A city recorded a population of over 300,000 (New York) Multiple cities recorded populations of over 100,000 (New York, Baltimore, and New Orleans) This was the last census conducted by U.S. marshals, as starting in 1850 a temporary office would be set up for each census under the purview of the Department of the Interior. This was due to the Northern members of the Whig Party opposing the controversial claim in the 1840 census that free Black Americans in the Northern United States suffered from a higher degree of "insane" or "idiotic" behavior compared to enslaved Black Americans.