The United State Census of 1870, conducted during June 1870, determined the population to be 38,555,983 - an increase of 22.62 percent since the 1860 Census.<br><br>The 1870 Census was the first census to provide detailed information on the black population, only years after the culmination of the Civil War when slaves were granted freedom. The 1870 Census' population estimate is controversial, as many believed it underestimated the true population numbers, especially in New York and Pennsylvania.<br><br>Federal census takers were asked to record information about every person who was in each household on the census day. A census taker might have visited a house on a later date, but the information he collected was supposed to be about the people who were in the house on the census day. The basic census enumeration unit was the county. Each county was divided into enumeration districts, one for each enumerator. The completed forms were sent to the Commerce Department's Census Office in Washington, D.C.<br><br>Federal censuses are usually reliable, depending on the knowledge of the informant and the care of the census enumerator. Information may have been given to a census taker by any member of the family or by a neighbor. Some information may have been incorrect or deliberately falsified.
