PTRC | Finding Older Patents

Patents produced before 1976 can be tricky to find. If you have the patent number, or are searching for all the patents produced with a specific classification number, you can do this on the USPTO web site.

  1. Click on "Quick Search" in the green Issued Patents box.
  2. Add your search terms and change the appropriate Field index to select "Patent Number" or "Current U.S. Classification Code", depending on which field you are searching.

More likely, you are looking for a specific patent without knowing either the patent number or the current classification code. You might, for instance, know the inventor's name, or the name of the invention. In this case, you will need to consult the following print indexes at the D.H. Hill Library:

Print Indexes

1790 - 1873: Subject-Matter Index of Patents (vol. 1-2 inventions; vol. 3 inventors)

1846 - 1925: Annual Report of the Commissioner of Patents

  • A 1.1: 1850 - 1861 (Annual Report of the Department of Agriculture)
  • C 21.1: 1846 - 1925 (also labelled as Patent Office Reports)

1926 - 1996: Index of patents issued from the United States Patent Office

  • (later years linked from Later Title)
  • Available at SuDoc C 21.5/2:

Print Weekly Announcements (Official Gazette)

1872+ : Official Gazette of the United States Patent and Trademark Office. Patents.

Digitized Versions of Print Indexes and Gazettes

Some of the historical publications of the United States Patent Office have been digitized, and are available through the Internet Archives and/or GoogleBooks.