The formal legislative process begins when a member of Congress, in the Senate or House of Reperesentatives, introduces a bill. After a bill is introduced, it is assigned a bill number, gets printed, and usually is referred to one (or more) committees in its originating chamber. Sometimes, a bill may go directly to the full chamber for a vote, without a committee vote, but that is unusual.
Bill numbers are assigned in the order in which they are introduced, starting at the beginning of each two-year session of Congress. The first part of the citation includes a reference to the chamber of origin (H.R. or S.) and the assigned number. Example: H.R. 108 or S. 24. The bill number stays the same through each legislative stage. House and Senate bills are numbered separately, in chronological order in each chamber. For example, identical bills might get introduced simultaneously in each chamber, but would be numbered chronologically from the originating chamber. So, H.R.135 might be identical to S. 20. at introduction.
The bill text may be amended several times before passage. Comparing the different versions may (or may not) provide insight into the intended meaning of the law. Bill versions can be particularly helpful interpretation tools when reviewed with other documents created at the time of the amendments. The other documents might provide context for the changes. For a discussion of bill versions, see How Our Laws Are Made (2007).
GovInfo.gov: Official versions, 103rd Congress (1993-94)-present.
Congress.gov: Covers the 93rd Congress (1973-74)-present. Official versions.
ProQuest Congressional: Legislative Histories, Bills & Laws--Bills, 100th Congress (1987-88) to present, and some older materials. Coverage years vary by document type. Check the advanced search page menu. PDFs of official documents.
ProQuest Legislative Insight: Selected, 71st Congress (1929) to present; access Legislative Insight via the law library landing page. PDFs of official documents.
HeinOnline: Official versions, coverage varies for bills, but always check Hein if Proquest does not have an older document.
Westlaw: Bills from 104th Congress (1995-96)-present; and various legislative history materials. No PDFs
Lexis: Bills from 101st Congress (1989-90)-present; some older legislative history documents. No PDFs
Researchers looking for bills that fall within the gaps in coverage can take any one of the following steps.