Public bills pertain to matters that affect the general public or classes of citizens, while private bills affect just certain individuals and organizations.
A private bill provides benefits to specified individuals (including corporate bodies). Individuals sometimes request relief through private legislation when administrative or legal remedies are exhausted. Many private bills deal with immigration–granting citizenship or permanent residency. Private bills may also be introduced for individuals who have claims against the government, veterans' benefits claims, claims for military decorations, or taxation problems. The title of a private bill usually begins with the phrase, "For the relief of. . . ." if a private bill is passed in identical form by both houses of Congress and is signed by the president, it becomes a private law.
When bills are passed in identical form by both Chambers of Congress and signed by the president (or repassed by Congress over a presidential veto), they become laws." (U.S. Senate)
Private Law – "A private bill passed by both the House of Representatives and the Senate in identical form that has been enacted into law. Private laws only affect a private individual or individuals. A Private law is designated by the abbreviation “Pvt. L.” followed by the Congress number (e.g. 104), and the number of the law. For example: Pvt. L. 104-1" (Library of Congress)
Public Law – "A bill or joint resolution passed by both the House of Representatives and the Senate in identical form that has been enacted into law. Public laws affect the entire nation. A Public law is designated by the abbreviation 'Pub. L.' followed by the Congress number (e.g. 108), and the number of the law. For example: Pub. L. 108-211 (Library of Congress)
Background Information on the Topics
Government Documents/Law Review Articles