Use the subject index to search for your topic in the most likely departments. At the end of each entry you will find a Reference Bibliography number (e.g., T104a-41.14). Look up this number in the Reference Bibliography that is in the last volume of the part you are using. There you will find the SuDoc call number for the item you want.
Congressional Universe - contains indexing and some full-text for Congressional Indexes, 1789 - 1969.
Poore, Ben P. A Descriptive Catalogue of the Government Publications of the United States, Sept. 5, 1774 – March 4, 1881. Docs Index, KF 12.P66 1885
Indexes are located in the US Documents Garden Level and at Creekside (these are available upon request).
A Descriptive Catalog of the Government Publications of the U.S., 1774-1881, Poore, Benjamin P., 1 vol.
(Login required for) Nineteenth Century Masterfile - include: U.S. patents, 1790-1873; U.S. government publications, 1774-1881; British House of Commons and House of Lords, 1803-1830. U.S. government publications, 1774-1881; British House of Commons and House of Lords, 1803-1830
Checklist of public documents containing debates and proceedings of Congress from the First to the Fifty-third Congress, together with miscellaneous lists of documents, and historical and bibliographical notes.
Index to U.S. Documents Relating to Foreign Affairs 1828-1861, Hasse, Adelaide