For the first time in the history of the United States census, enumerators of the 1850 census were instructed to record the names of every person in the household. Added to this, enumerators were presented with printed instructions, which account for the greater degree of accuracy compared with earlier censuses. Enumerators were asked to include the following categories in the census: name; age as of the census day; sex; color; birthplace; occupation of males over age fifteen; value of real estate; whether married within the previous year; whether deaf-mute, blind, insane, or "idiotic"; whether able to read or write for individuals over age twenty; and whether the person attended school within the previous year. No relationships were shown between members of a household. The categories allowed Congress to determine persons residing in the United States for collection of taxes and the appropriation of seats in the House of Representatives.
The 1850 Census includes the following states and territories: Alabama, Arkansas, California, Connecticut, Delaware, District of Columbia, Florida, Georgia, Illinois, Indiana, Iowa, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota Territory (includes Dakota area), Mississippi, Missouri, New Hampshire, New Jersey, New Mexico Territory (includes Arizona area), New York, North Carolina, Ohio, Oregon Territory (includes Washington and Idaho areas), Pennsylvania, Rhode Island, South Carolina, Tennessee, Texas, Utah Territory, Vermont, Virginia (includes West Virginia counties), Wisconsin.
There were no substantial state- or district-wide losses.
The official enumeration day of the 1850 census was 1 June 1850. All questions asked were supposed to refer to that date.
Taken from Szucs, Loretto Dennis, "Research in Census Records." In The Source: A Guidebook of American Genealogy, ed. Loretto Dennis Szucs and Sandra Hargreaves Luebking (Salt Lake City: Ancestry, 1997).
In addition to the full set of films viewable online at Ancestry.com, many counties have been transcribed and placed online through volunteer efforts at USGenWeb (drill down to the county of interest).
Most larger genealogy libraries are also likely to have a full or regional set of census microfilm onsite. Local LDS Family History Centers have the ability to order films from Salt Lake upon request.
FamilySearch is in the process of transcribing and imaging the 1850 census and has posted it to their new pilot site. The search is currently (July 2008) missing Missouri, Indiana, Virginia, Alabama, Georgia, Mississippi, and Louisiana.
There is an optional template for adding 1850 U.S. census data to pages in a table format: Template:1850-UScensusData.