U.S. Code: This is the United States Code from the official U.S. government website, GovInfo. It is presented in the same format of six-year reissuances with annual cumulative supplements as the print edition. The data source for it is the same as the one the Government Printing Office uses to prepare the print version.

U.S. Code from HOLC: The House Office of the Law Revision Counsel is the official classifier of the U.S. Code. It is an integrated, current version of U.S. Code, updated by new laws shortly after they are enacted. The data source for it is the same as the one the Government Printing Office uses to prepare the print version. Note: The House Office of the Legislative Counsel is not the same as the House Office of the Law Revision Counsel. The HOLC assists House members and committees in the drafting of legislation and related tasks. The OLRC compiles, revises, and publishes the United States Code, which arranges all general and permanent U.S. laws by subject matter.

U.S. Statutes at Large (1951-present): This is the U.S. Statutes at Large from the official U.S. government website, GovInfo. It is the print edition digitized.

U.S. Public Laws from Congress.gov (1951-present): This is the official, and fastest, source for public laws as they are enacted.

U.S. Statute Compilations from HOLC: From the House Office of the Legislative Counsel, these are compilations of public laws that either do not appear in the U.S. Code or that have been classified to a title of the U.S. Code that has not been enacted into positive law. Each Statute Compilation incorporates the amendments made to the underlying statute since it was originally enacted. Note: The House Office of the Legislative Counsel is not the same as the House Office of the Law Revision Counsel. The HOLC assists House members and committees in the drafting of legislation and related tasks. The OLRC compiles, revises, and publishes the United States Code, which arranges all general and permanent U.S. laws by subject matter.

U.S. Code from the LII: The LII's version of the code is drawn from the OLRC database, and is almost as current (there is a very slight lag).

U.S. Code from Justia: This code appears to be fairly up-to-date, but there is no "current through" date posted, so relying on it is problematic.

U.S. Code from FindLaw: The FindLaw code is not very current, even though it is an integrated, updated code. At this writing, it is over four-and-a-half years behind the OLRC official version. Relying on this version of the code is problematic.

U.S. Code from HeinOnline: These are PDFs of print version of the U.S. Code, which is issued every six years with annual cumulative supplements. [WCL proxy link]

U.S. Statutes at Large from HeinOnline (1789-present): These are PDFs of print version of the U.S. Statutes at Large [WCL proxy link]