Primary sources are increasingly available online as historical societies, museums, and other organizations digitize their primary source collections. Try adding the terms below to your online search:
A list of several digital library projects is listed on Wikipedia. Below are a few major portals that help you access digitized primary sources.
Note: Academic departments and disciplines define 'primary sources' differently. Check with your instructor if you aren't sure about what counts as a primary source for an assignment.
With that being said, these are some general characteristics of primary sources:
Use the Libraries' WorldCat catalog (the main search box on the library homepage) to find primary sources. Just type in your usual search terms and add one of the terms listed below!