For most UCI researchers looking for the legislative history of a federal law, Legislative Insight is the best starting point. Their collection is weaker for laws before approximately 1900, so if you're looking for information about an older law, check one of the other options. Legislative Insight provides a list of which Congresses are covered on its front page. No coverage of state laws.
Compiled federal legislative histories are included in the sources below. These can be helpful if your law is not included in Legislative Insight, or if you want more secondary source coverage than Legislative Insight provides.
Compiled legislative histories are existing collections of all the relevant Congressional documents leading up to a particular act's passage. Tip: Some bills are introduced in several Congresses before they pass, and there can be interesting commentary in documents from earlier Congressional sessions.
Compiled legislative histories can include:
Using a compiled history saves time because documents have already been gathered.
Legislative Insight — the Best Bet resource above — lets you search by the popular name of an act, like "PATRIOT Act" or "Patient Protection and Affordable Care Act."
Citations that you'll need for other resources include:
Lexis or Westlaw also have Popular Names tables. And the Office of Law Revision Counsel provides a free Popular Name Tool:
To find citations to Public Laws and Statutes at large, you can start with a U.S. Code section. Bring up the section in Lexis or Westlaw (or find it in print) and read the notes following the section.
Example from Lexis Advance for 42 USCS § 14131 (as of 2015):
The note shows that the section was:
Important tips about the historical note above:
To find corresponding bill numbers, click through to the Public Law or Statutes at Large. If there's no click-through access because the law is too old, one option is to check HeinOnline.