Public and private laws are also known as slip laws. A slip law is an official publication of the law and is competent evidence admissible in all state and Federal courts and tribunals of the United States. Public laws affect society as a whole, while private laws affect an individual, family, or small group.
After the President signs a bill into law, it is delivered to the Office of the Federal Register (OFR), National Archives and Records Administration (NARA) where it is assigned a law number, legal statutory citation (public laws only), and prepared for publication as a slip law. Private laws receive their legal statutory citations when they are published in the United States Statutes at Large.
Prior to publication as a slip law, OFR also prepares marginal notes and citations for each law, and a legislative history for public laws only. The Office of the Federal Register (OFR), National Archives and Records Administration (NARA) prepares the law by assigning it a law number and a legal statutory citation. The law number is determined by three factors, whether the law is public or private, the Congress that enacted the law, and the order of the ratification of the law.
For example, the citation for the 6th public law enacted by the 107th Congress would be: Pub. L. 107-6
And the citation for the 11th private law enacted by the 112th Congress is: Pvt. L. 112-11
At the end of each Congressional session, the slip laws are compiled and bound into volumes entitled the Statutes at Large. The public and private laws are then referred to as session laws.
adapted from govinfo.gov