A primary source is a document or other sort of evidence written or created during the time under study, or by one of the persons or organizations directly involved in the event. Primary sources offer an inside view of a particular event. Some types are:
Original Documents (excerpts or translations acceptable)
Creative Works
Relics or Artifacts
This excellent video succinctly explains the difference between primary and secondary sources. Complete with examples and tips on how to locate primary resources in the library.
Publications created by the United States Congress during the process leading up to the enactment of U.S. Public Laws.