1840 United States census


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 west of Washington, D.C., near Weston, Virginia.
This was the first census in which:
  • A state recorded a population of over two million
  • A city recorded a population of over 300,000
  • Multiple cities recorded populations of over 100,000
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.

Controversy over statistics for mental illness among Northern blacks

The 1840 census was the first that attempted to count Americans who were "insane" or "idiotic". Published results of the census indicated that alarming numbers of black persons living in non-slaveholding States were mentally ill, in striking contrast to the corresponding figures for slaveholding States.
Pro-slavery advocates trumpeted the results as evidence of the beneficial effects of slavery, and the probable consequences of emancipation. Anti-slavery advocates contended, on the contrary, that the published returns were riddled with errors, as detailed in an 1844 report by Edward Jarvis of Massachusetts in the American Journal of the Medical Sciences, later published separately as a pamphlet, and in a memorial from the American Statistical Association to Congress, praying that measures be taken to correct the errors.
The memorial was submitted to the House of Representatives by John Quincy Adams, who contended that it demonstrated "a multitude of gross and important errors" in the published returns. In response to the House's request for an inquiry, Secretary of State John C. Calhoun reported that a careful examination of the statistics by the supervisor of the census had fully sustained their correctness. The returns were not revised.

Census questions

The 1840 census asked these questions:
  • Name of head of family
  • Address
  • Number of free white males and females
  • * in five-year age groups to age 20
  • * in 10-year age groups from 20 to 100
  • * 100 years and older
  • number of slaves and free colored persons in six age groups
  • number of deaf and dumb, by race
  • number of blind, by race
  • number of insane and idiotic in public or private charge, by race
  • number of persons in each family employed in seven classes of occupation
  • number of schools and number of scholars
  • number of white persons over 20 who could not read and write
  • number of pensioners for Revolutionary or military service

    Data availability

No microdata from the 1840 population census are available, but aggregate data for small areas, together with compatible cartographic boundary files, can be downloaded from the National Historical Geographic Information System. A compendium of data from the sixth census, organized by States, counties, and principal towns is available .

State rankings

RankStatePopulation
1New York2,428,921
2Pennsylvania1,724,033
3Ohio1,519,467
4Virginia1,239,792
5Tennessee829,210
6Kentucky779,828
7North Carolina753,419
8Massachusetts737,699
9Georgia691,392
10Indiana685,866
11South Carolina594,398
12Alabama590,756
13Maine501,793
14Illinois476,183
15Maryland470,019
16Missouri383,702
17Mississippi375,651
18New Jersey373,306
19Louisiana352,411
20Connecticut309,978
21Vermont291,948
22New Hampshire284,574
XWest Virginia224,537
23Michigan212,267
24Rhode Island108,830
25Arkansas97,574
26Delaware78,085
XFlorida54,477
XIowa43,112
XDistrict of Columbia33,745
XWisconsin30,945

City rankings