The Copyright Office was established in the Library of Congress in 1870. It is the official registrar of copyrights in the U.S. Its mission is "to promote creativity by administering and sustaining an effective national copyright system."
Government Documents has a partial collection of Copyright Office publications. Our holdings are fully cataloged and searchable in OneSearch.
Catalog of copyright entries (LC 3.6/6:)
The Catalog of copyright entries is also available online from the Copyright Office (1978-present) or via HathiTrust or Google Books (older volumes).
Annual report of the Register of Copyrights for the fiscal year ending ... (GOVD Fiche LC 3.1:)
We also have many handbooks, guides, and general publications about copyright law, registering copyrights, and searching for them.