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Patents: How to Search for an Historical U.S. Patent

Guide to searching among United States and foreign patents (prior art) to determine whether an idea can be patented.

Searching for Older U.S. Patents

Index of Patents

SIBL has this annual from 1872 to the final print issue in 2002 (available electronically through 1973 from the Hathi Trust - keyword searchable, but only within the individual volumes). This title has been published under various names such as Annual Report of the Commissioner of Patents (1838 - 1925 available electronically from the Hathi Trust) and General Index of the Official Gazette. The Index to Patents lists patents by inventor and assignee name and by general subject. It provides the patent number, registration date, and the volume and page number where it can be found in the Official Gazette.

Early Unnumbered United States Patents, 1790 to 1836

This one volume index is the specially prepared companion to the microfilm copies of the U.S.'s early, unnumbered patents (i.e., those that were issued from 1790 to 1836). It lists these earliest patents by patent class, then alphabetically by invention title and by issue date. These lists give the specific microfilm reel number where the full text, specifications, and drawings are located.

Name and Date Patents, July 31, 1790 - July 2, 1836 | *R-SIBL T223.V3 .N36

A listing of the earliest patents issued by the U.S. Patent Office prior to 1836. Sometimes referred to as the "X" patents from the numbering system applied to them on a retrospective basis. This resource lists the patents in date order, with name and type of invention. Copies available to download here:

Patents x0001 - x1000 | Patents x1001 - x2000 | Patents x2001 - x3000 | Patents x3001 - x4000 | Patents x4001 - x5000 | Patents x5001 - x6000 | Patents x6001 - x7000 | Patents x7001 - x8000 | Patents x8001 - x9000 | Patents x9001 - x9902

Subject-Matter Index of Patents ... 1790 to 1873

This three volume set lists all patents granted from 1790 to 1873 alphabetically by the subject of the patent. It gives inventor's names, their residences, the registration date, and the patent number for those granted after 1836. There is no listing by inventor name or registration date in this set. Available electronically from the Hathi Trust.

More information for each year can be found in the annual reports from the Commissioner of Patents, which are available in the three volumes listed below or, electronically, from 1838 - 1925 (incomplete) in the Hathi Trust.

Digest of Patents: 1790 to 1839 (also from Hathi Trust)
Digest of Patents: 1839 to 1841 (also from Hathi Trust)
List of Patents: 1790 to 1847 (also from Hathi Trust)

These volumes include reprinted copies of the annual reports prepared by the Commissioner of Patents from 1790 to 1847. The information in them varies, but generally includes lists of the patents arranged alphabetically by subject of the patent or chronologically by issue date. The Early Unnumbered United States Patents,1790 to 1836 and Subject-Matter ndex of Patents  ... 1790 to 1873  (described above) present all the bibliographic information included in these separate volumes, but in a different format.

Plant Patent Directory

Produced by the National Association of Plant Patent Owners, this source indexes all plant patents granted from the beginning of the series in 1931 to 1993. It indexes plant patents by plant patent number, plant species, plant denomination, originator (inventor), and assignee.

Miniature of Cucifixion with image of Dominican nun (sponsor of book); and facing text page., Digital ID 1261532, New York Public LibraryU.S. Patents - Text and Images

Other topics in this guide:

United States Patent and Trademark Office (

Copies of patents, patent applications, and many other patent-related filings are available on the USPTO web site. Patent searching can be done directly on the USPTO's web site. Full text and images are available for patents from 1976 to the most recent Tuesday. Images, current classification numbers and patent numbers only are available for patents from 1790 to 1975. The USPTO's web page offers excellent information on all aspects of patents, including fee schedules, online versions of their most popular brochures, forms, and background information on patents.

In addition, U.S. patents are available from the European Patent Office's Espacenet website, and from Google Patents as well as various other free and fee-based online resources.

The full text and images of US patents from 1790 through 2011 in different formats are available from SIBL as follows:

Desciption Title//Years Format/Location
Utitlity Patents U. S. patents / 1790-1999 Microfilm *XFR-1 [Offsite]
Design Patents U. S. design patents / 1842-1999 Microfilm *XFR-10 [Offsite]
Plant Patents Plant pat. / United States Patent Office / 1931-1975 *VAC (United States. Patent Office. [Specifications and drawings of patents] Plant pat.)
Plant Patents [Microfiche: color illustrations] 1931-1995 [Patents No. 1 - 9,284] Microfiche [Not in CATNYP - Speak to a librarian for location of fiche].
Plant Patents United States patent. Plant. 1976-1993 *VAC (United States. Patent Office. [Specifications and drawings of patents] Plant pat.)
Plant Patents United States patent. Plant. 1994-current JSM 99-245
Reissue Patents CDR File (Corrections, Disclaimers, Reissues). 1838-1995 *XFR-2
Defensive Publications Defensive Publications. 1975-1985 *XFR-20
Statutory Invention Registrations United States Statutory Invention Registration *XFR-23
Reexamination Certificates CDR File (Corrections, Disclaimers, Reissues). 1981-1995 *XFR-2
U.S. patent documents on CD-ROM USAPAT / 1994-1999 CD-ROM *WSC-421
U.S. patent documents on DVD-ROM USAPAT / 1790 to 2011 DVD-ROM *WSD-421

Patent and Trademark Documents Timeline