All Supreme Court opinions, from 1759 to the present. Federal court of appeals and federal district court opinions from about 1925 to the present. (The texts of the cases are drawn from various sources, including Justia and Cornell's Legal Information Institute.)

Supreme Court opinions from 1754 to the present and Court of Appeals decisions from 1950 to the present. (Content is from fastcase.)

All Supreme Court opinions, and Federal court of appeals opinions from 1925 to the present. (Ravel offers a "Premium" option that includes Federal district court opinions from 1933 to the present.)

Casetext has all Supreme Court opinions, federal court of appeal opinions from 1925 to the present, and Federal district court opinions from 1980 to the present.

Supreme Court cases from 1759 to the present. Optimized for browsing rather than searching.

Opinions from 2007 to the present.

Court of Appeals opinions from 1951 to the present. (Optimized for browsing rather than searching.)

Opinions from the federal district courts. Coverage varies. For some districts, the earliest cases are from 1999. (Optimized for browsing rather than searching.)

Official site with information and news about the federal courts, plus a Court Locator that links to all courts. Also includes the guide Understanding the Federal Courts.

Official site, with news; court information, local rules, general orders, calendars, announcements, FAQs, court documents. Also available: published opinions and unpublished opinions from 1995 to the present.

Official site, with court information, documents from cases of interest, FAQs, and local rules. Docket information is available for a small fee (about 10¢ per page) at the court's PACER site.

A browsable and searchable version of the U.S. Code. Use the "USC-Prelim" tab to see the updated text of the laws you are researching. [As of May 1, 2012, the updated text was current as of Tuesday, February 21, 2012 (up to Public Law 112-90). For updates, consult the U.S. Code Classification Tables.]

From the House of Representatives, Office of the Law Revision Counsel. [As of May 7, 2014, this version of the U.S. Code was current as of April 18, 2014. For updates, consult the U.S. Code Classification Tables.]

Bills and resolutions (summaries from 1973 to the present and full text of bills from 1989 to the present), Public Laws (from 1989 to the present), the Congressional Record (from 1989 to the present), committee reports (from 1995 to the present), other committee information and related sources, data on Presidential nominations, treaties, and information about treaty actions. Thomas also links to other federal legislative and agency sites.

Documents & information from all three branches of the federal government. Congressional/legislative information in the FDSys collections includes: the U.S. Code; public and private laws; the Statutes at Large, congressional bills; the Congressional Record; the Serial Set (for committee reports); congressional hearings, and more. For searching, use the FDsys Advanced Search feature.

In-force federal rules and regulations. This official web version of the CFR is only as current as the print version. For searching, use the FDsys Advanced Search feature. To update, use: List of CFR Sections Affected. (From the Government Printing Office; covers 1996/97 to the present.)

The eCFR's disclaimer states: "The Electronic Code of Federal Regulations (e-CFR) is a currently updated version of the Code of Federal Regulations (CFR). It is not an official legal edition of the CFR." (The eCFR is produced by the National Archives and Records Administration's Office of the Federal Register (OFR) and the Government Printing Office.)

A searchable and browsable CFR. To update a section, use the "Currency" tab. Also includes: links to U.S. Code provisions providing rulemaking authority; links to proposed rules in the Federal Register.

Daily publication of new and proposed federal regulations, presidential executive orders, and important notices from federal agencies. To find regulations, use the FDsys Advanced Search feature or the 2013 Federal Register Index. (From the Government Printing Office; covers volume 59 (1994) to the present.)

Unofficial but very user-friendly version of the Federal Register. Features include: filtering and browsing by topic, agency, date, type of notice or regulation. Links to official PDF versions of regulations. Also includes an online index. Covers 1994 to the present.

Proposed regulations - for review and comment. (Also includes regulatory agendas, final rules, and texts of comments.)

New and proposed federal regulations, executive orders, administrative orders, notices & proclamation. You can search, browse by date and agency, and subscribe to automatic updates.

A listing from USA.gov, the U.S. Government's official web portal. USA.gov also offers an A to Z list of U.S. government departments and agencies.