Federal

• Constitution of the United States

Statutes

• List of United States federal legislation
• Acts listed by popular name, via Cornell University
• United States Statutes at Large
  • Volumes 1 through 18, 1789–1875, via Library of Congress
• Public Laws (PL)
  • Current Congress only, via the U.S. Government Printing Office
  • 104th Congress through current Congress, via the U.S. Government Printing Office
• United States Code (USC)
  • U.S. Code, via Cornell University
  • U.S. Code, via the U.S. Government Printing Office
  • U.S. Code, via FindLaw.com
  • U.S. Code via house.gov
  • U.S. Code, via USCodeSurf.com

Administrative regulations

• Code of Federal Regulations (CFR)
• List of United States federal executive orders (EO)

Court precedents

• Findlaw Cases and Codes
• United States Reports – Supreme Court cases
  • Lists of United States Supreme Court cases
• Federal Reporter – Courts of Appeals and Federal Claims cases
  • List of notable United States Courts of Appeals cases
• Federal Supplement – District Courts cases
• Federal Appendix – "Unpublished" cases

States

• State constitutions

Court precedents

• List of notable United States state supreme court cases
• Findlaw Cases and Codes

Statutes

• Findlaw State Government page

Regulations

• List of State Administrative Codes and Registers from the National Association of Secretaries of State

Local codes and ordinances

• American Legal Publishing's Code Library
• E-Codes from the General Code Corporation
• Municipal Code Corporation's Online Library

Secondary sources

• List of Uniform Acts (United States)
• American Jurisprudence
• Corpus Juris Secundum
• Restatements of the Law
• Casebooks
• Law reviews