National Archives and Records Administration: Great Lakes Region [IL]
If you happen to be looking for federal primary sources from Ohio, Indiana, Minnesota, Wisconsin, Michigan, or Illinois, a good spot to check is the Chicago office of the National Archives and Records Administration. Records available include bankruptcy records, Chinese Exclusion case files from Chicago and St. Paul, Michigan and Illinois Selective Service System Name Index records, and naturalization records. Other topics represented in the collections include, but aren't limited to, African American history, Depression era history, disasters, espionage, and maritime history.
Consider looking through the site's finding aids to get a sense of the collections available on location.
When visiting, be ready with an official photo ID and willingness to fill out a short form concerning your interests. Leave your pens behind (pencils are permitted), and prepare to leave your belongings in a locker or in your car.
Looking for more directed opportunities? Check out the archives' upcoming events. If you teach in Illinois or Indiana, you may even be eligible for continuing education credit.
In addition to the aforementioned public programs, there are workshops designed specifically for teachers. Find them (and more opportunities) under the Workshops heading.
Archivists are ready and willing to help your students define their research topics and select appropriate primary sources, for National History Day projects or other endeavors.