Statutes at Large
The law that is actually enacted by Congress and signed by the president can be found in the Statutes at Large, a giant chronological compilation of everything Congress has enacted, with subsequent amendments and repeals.
The United States Statutes at Large is the collection of every law, public and private, ever enacted by the Congress, published in order of the date of its passage. These laws are codified every six years in the United States Code, but the Statutes at Large remains the official source of legislation. Until 1948, all treaties and international agreements approved by the Senate were also published in the set. In addition, the Statutes at Large includes the text of the Declaration of Independence, Articles of Confederation, the Constitution, amendments to the Constitution, treaties with Indians and foreign nations, and presidential proclamations.
A citation to the Statutes at Large - for example "26 Stat. 8 (1890)" - begins with the Volume number (in this example, the citation refers you to Volume 26) and the page number of the Volume (here, page 8). The Statutes at Large is also browseable by session, congress, and date:
For more information on the use of the Statutes at Large, please see the Law Library's research guide "Federal Statutes: A Beginner's Guide."