Getting Started with Primary Sources
A guide to finding primary sources, includes curated Primary Source Sets of documents and images. On the left-hand side of the screen there are numerous Topics and Eras options to select from and search thru. (Notice how Primary Source Set is selected as the Classroom Material Type.)
In a similar vein there is also the U.S. History Primary Sources Timeline featuring nine different periods in American history from the 1600s to 1968. Clicking in them will provide you with an overview and then selected documents from the time period.
An alternate search technique is to Google Library of Congress, primary resources, and then your subject of study. Example: Library of Congress primary resources Roosevelt site:.gov
Including the site:.gov will limit the Google results to official government sites only.