You can access all states from this site. By going to the counties you can find genealogy helpers. This is a very well done website with gobs of information. This is a well done site and they keep adding more. This site located in Chicago is a good place to start.
Every state has a college library that is designated as a federal repository.
Each state is required to have at least one. They contain phone books of major cities, city directories, old Polk directories, and old newspapers. The federal goverment releases information every few years in huge amounts. These libraries are HUGE and have a wealth of information. Now the law says that mature adoptees age 19 or older can receive their identifying information only when there is a waiver on file for consent to release the information in the adoptee's file.