Of primary interest to genealogists are service records and pension records. Many records are available through the National Archives.
What happened to the 1890 U.S. Census? A fire broke out in the basement of the Commerce Building in Washington, D.C.on January 10, 1921. The census records were stored improperly in the basement and were soaked with water and no restoration efforts were made to save the documents. The damaged records were destroyed sometime between 1933 and 1935 when they were deemed no longer necessary.
Library of Congress, Washington, D.C. has manuscripts, publications and microfilms of a wide range of materials useful to genealogical research. Their website is free and easy to use.
The U.S. Federal Census is taken every 10 years on a designated census day by an "enumerator" in a specific area called an enumeration district. The first census was done in 1790; there are no censuses before 1790.
DNA: (Deoxyribonucleic Acid) The chemical name for the molecule that carries genetic instructions in all living things. The DNA molecule consists of two strands that wind around each other to form a shape known as the double helix.