About Public and Private Laws
"Most laws passed by Congress are public laws. Public laws affect society as a whole. Public law citations include the abbreviation, Pub.L., (or P.L.) the Congress number (e.g. 107), and the number of the law. For example: Pub.L. 107-006 (or P.L. 107-6).
Affect an individual, family, or small group. Private laws are enacted to assist citizens that have been injured by government programs or who are appealing an executive agency ruling such as deportation. Private laws citations include the abbreviation, Pvt.L., the Congress number (e.g. 107), and the number of the law. For example: Pvt.L. 107-006." (GPO: Public and Private Laws)
Public laws are initially published as "Slip Laws" and later published in United States Statutes at Large, the permanent collection of all laws and resolutions enacted during each session of Congress. The Statutes at Large is prepared and published by the Office of the Federal Register (OFR), National Archives and Records Administration (NARA).