All Supreme Court opinions, from 1791 to the present (with selected coverage of pre-1790 decisions). 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.)
Ravel's free "Open" option currently offers all Supreme Court opinions, and Federal court opinions from about 1925 to the present. Ravel & Harvard plan to offer all US case law — including all published federal court opinions — for free via their joint Free the Law project.) [In June 2017 LexisNexis acquired Ravel. By 2018, Ravel will be completely incorporated in LexisNexis.]
Ravel & Harvard are digitizing all published state cases and are offering them for free via their joint Case Law Access project.
Casetext has all Supreme Court opinions, federal court of appeal opinions from 1925 to the present, Federal district court opinions from 1980 to the present, and state appellate court cases from 1925 to the present.
The official web site of the Court. Offers: same-day slip opinions; the current docket; oral argument transcripts; merit briefs (via the ABA); court rules; case handling guides; calendars and schedules; public and visitor information.
Official site, with news; court information, local rules, general orders, calendars, announcements, FAQs, court documents. Also available: published opinions and unpublished dispositions from about the last 10 years or so.
A browsable and searchable version of the U.S. Code. [As of April 11, 2016, the updated text was current as of about July 2015 (up to Public Law 114-38). For further updates, consult the U.S. Code Classification Tables.]
From the House of Representatives, Office of the Law Revision Counsel. [As of April 11, 2016, this version of the U.S. Code was current as of April 10, 2016. For updates, consult the U.S. Code Classification Tables.]
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.)
A convenient, currently updated (but not official) version of the Code of Federal Regulations (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 "eCFR" or "Updates" tabs. Also includes: links to U.S. Code provisions providing rulemaking authority; links to proposed rules in the Federal Register via the "Rulemaking" tab.
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 2016 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: flexible "Search" function; 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.