For major legislation, someone may have already compiled the documents, or at least created a list of citations to them.
Checking the sources on this page first may save you lots of time.
Federal Legislative Histories: An Annotated Bibliography and Index to Officially Published Sources, by Bernard Reams, call number: KF 42.2 1994 Law Reference.
Sources of Compiled Legislative Histories: A Bibliography of Government Documents, Periodical Articles, and Books, compiled by Nancy P. Johnson, call number: KF 42.2 1979 Law Reference Desk. Also available to the USF community as part of the U.S. Federal Legislative History Library on HeinOnline. (For details, see Digital Sources, above).
The Zief Law Library also has compiled legislative histories on microfiche through Congressional Information Service's CIS Index to Publications of the United States Congress, call number: KF 49 .C62 Law Microforms).
Selected compiled legislative histories in print at the Zief Library. Try a "Doncore" search in Ignacio, and include the phrase "legislative history" in your search. (You can use the Doncore Search box on this page to run your search.)