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.

Pro-slavery advocates trumpeted the results as evidence of the beneficial effects of slavery, and the probable consequences of emancipation.

[1] 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,[1][2] and in a memorial from the American Statistical Association to Congress, praying that measures be taken to correct the errors.

[3] 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.

[4] 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.