Browsing
In public libraries American history has a 973 call number and New Jersey history has a 974 call number.
In academic libraries American history has an E call number and New Jersey history is in the F 131 - F145 range.
Searching for primary sources
Look for the following subject subheadings when searching for primary sources
At times freely available online sites like Google Books, HathiTrust, and Project Gutenberg will have useful materials; the Internet Archive might also.