This search will allow you search for American publications from 1866-1877. If your topic is about something that occurred after this time period, you will not find useful materials here.
There are some keywords that you can look for and use to your advantage while searching for historical data. If you are looking for specific documents, you should search for that title information. If you're looking for personal accounts, letters, etc., regarding a specific historical period, there are several things to try.
1. Determine the subject heading for the event or era
2. Consider using words such as:
3. Search for key figures from historical events as authors rather than as subjects
Check out this great resource from the Library of Congress. They have indexed primary sources from every state in the union. Simply click on the map to select the state you're interested in and browse the results.
The map looks like this: