Historical Background: Article I, Section 2, of the Constitution requires an "Enumeration" of the population of the United States every ten years. The first census began on the first Monday in August, 1790, barely a year after the Inauguration of President Washington. There have been twenty-one censuses since the first, the most recent one taken on April 1, 2000.
Atlas of County Boundary Changes in Virginia, 1634-1895 - Reference Room, 4th floor: G1291.F7 D6 1987
Shows the evolution of counties in Virginia from colonial times to the end of the 19th century. See also the Atlas of Historical County Boundaries, which contains information for all the states, from the Newberry Library.
Descriptions of Census Enumeration Districts, 1830-1950 - Microfilm cabinets, Government Information Reading Room.
Available: Virginia only [Gov Info Microfilm #7903].
These are descriptions of the physical area in which each census enumerator took the census. Literally, they describe the neighborhoods and roads the enumerator walked up and down to interview households.
Guide to Genealogical Research in the National Archives - Shelved on Row 13, Gov Info Reading Room
Describes a wide range of Federal records available for genealogical research in the National Archives. Chapter one, "Census Records" is particularly useful for its detailed descriptions and examples. For a full description of the title see Publications web page linked from the the National Archives' Genealogy Page.
Map Guide to the U.S. Federal Censuses, 1790-1920 - Shelved on Row 13, Gov Info Reading Room
Shows county outline maps at ten-year intervals, the old county boundaries being superimposed over the modern lines.
What census records are available generally? By law census records about individuals must be 72 years old before being released publicly. The only exception to the 72-year confidentiality requirement is that age information about deceased individuals may be released to the decedent's heirs. See Census Information about Individuals for more information. The Census Age Search page is also helpful if you are seeking individual information.
Destroyed Schedules: No schedules are known to exist for 1790 for Delaware, Georgia, Kentucky, New Jersey, Tennessee, and Virginia. Only scattered schedules for 1800 are extant. Apparently, both the 1790 and the 1800 missing schedules were destroyed during the British attack on Washington during the War of 1812. The 1790 schedules for Virginia were based on state enumeration's done about 1785.
The 1890 schedules were almost all lost when a fire broke out in the Department of Commerce building in January 1921.
Using the NARA Census guides to find microfilm name rolls.
1790-1890 - Click on the census you are interested in and see which reels you need for your county. Also, consult red census microfilm catalogs on Aisle 13 in Gov. Info Reading Room.
1930 - To locate microfilm roll numbers for the 1930 Census for Virginia see How to Research the 1930 Census Microfilm - pick the state in the upper left box, go to the lower half of the page and pick your county, then type your place in on the last page. You'll get a list of microfilm reels which include your place.
1940 - The 1940 Census is not yet fully indexed. In order to find persons in states which have not been indexed it's helpful to know where they lived - or the enumeration district they lived in. This site can help you identify the enumeration district.
Indian Census name rolls