Primary resources are original works and can be written, visual, creative, administrative, etc. These are often the objects of study in addition to pieces of evidence.
Where do you find primary sources? It really depends on the type of source. I have put some examples in the column to the right, but ultimately you will need to decide what kind of source you are trying to find and then use a specific website or database to find it. (This is a great time to consult with a librarian as we can usually point you in the right direction pretty quickly.) A lot of information is available online, but you might also have to physically visit certain archives and special collections if the material you want to use is not digitized.
In The Information-Literate Historian, Jenny Presnell describes nine categories of primary sources:
Public Records - census records, court records, wills, tax records, etc.
Official Records - laws, civil codes, legislative hearings, treaties, etc.
Personal Documents (manuscripts) - letters, diaries, oral histories, financial records, etc.
Artifacts/Relics - clothing, furniture, tools, music, art, and other items people make and use
Organizational Documents (archives) - meeting minutes, financial records, correspondence, etc.
Images - photographs, drawings, cartoons, posters, videos, graphics, paintings, etc.
Architecture, City Plans, and Maps - buildings, blueprints, plans, models, etc.
Media and Other Mass Communication - newspapers, magazines, journals, radio, tv, twitter, facebook, websites, etc.
Literary Texts - novels, plays, poems, essays, etc.