The U.S. Copyright Office has been housed in the Library of Congress since 1870, when copyright applicants began being required to submit two copies of their works.
Notes on verification
Confirmed by multiple independent, authoritative sources including the U.S. Copyright Office's own historical records and the Library of Congress's official publications, with consistent details on the 1870 date and two-copy deposit requirement. [cascade flags: wikipedia_dropped_other_sources_exist | tier=bronze indep_score=0.539 clusters=2 claim_tier=notable]
Sources
- Library of Congress | Definition, History, & Facts | Britannica (seed:culture_and_philosophy)
- https://www.copyright.gov/history/copyright-exhibit/history-co/ (corroboration)
- https://www.copyright.gov/about/ (corroboration)
- https://www.loc.gov/loc/lcib/9516/copyright.html (corroboration)