To cite a law or statute correctly, name the source with its standard abbreviation, point to the exact section or page, and add the edition or decision year in parentheses. That four-part logic — source, locator, year, and where needed a court or publisher — is what every legal citation is built from, whether you are writing about a federal statute, a regulation, a constitutional clause, or a court opinion. The formats below cover how to cite laws and statutes in each of those categories.
Federal Statutes
Federal statutes live in the United States Code, which sorts the general and permanent laws of the United States into 54 subject titles.1GovInfo. United States Code A standard U.S. Code citation has four parts: the title number, the abbreviation U.S.C., a section symbol and section number, and the edition year in parentheses.
42 U.S.C. § 12101 (2018)
Here, 42 is the title (Public Health and Welfare), U.S.C. identifies the official federal code, § 12101 pinpoints the section, and (2018) is the edition year.
Official vs. Annotated Codes
The U.S.C. is the official version. Two commercial alternatives, the United States Code Annotated (U.S.C.A.) and the United States Code Service (U.S.C.S.), add case summaries and cross-references and tend to update faster. Formal citation calls for U.S.C. unless the official code does not yet include the provision, in which case you substitute the annotated abbreviation, for example 42 U.S.C.A. § 12101.
New Laws Not Yet Codified
When a law is too new to have been folded into the U.S. Code, cite it by its Public Law number and its place in the Statutes at Large, the chronological record of every law Congress passes. A Statutes at Large citation gives the volume and starting page: 107 Stat. 25 means the law begins on page 25 of volume 107.2Library of Congress. Citations for and Popular Names of Statutes – Federal Statutes Once codified, switch to the U.S.C. form.
Federal Regulations
Agency rules appear in the Code of Federal Regulations, organized into 50 subject titles.3Legal Information Institute (LII). Code of Federal Regulations (C.F.R.) The C.F.R. citation mirrors the U.S.C.: title number, C.F.R., section symbol and section number, edition year in parentheses.
45 C.F.R. § 164.502 (2024)
45 is the title (Public Welfare), § 164.502 is the specific regulation, and (2024) is the edition year.
Federal Register Citations
Before a rule reaches the C.F.R. it appears in the Federal Register, the daily journal for proposed and final rules, notices, and executive orders. Cite the Federal Register when a rule has not been codified yet or when you want the reader to see the rule as originally published. The format is the rule’s title, volume number, Fed. Reg., starting page, and date of publication in parentheses.4Cornell University Law School. How to Cite Regulations, Other Agency and Executive Material
Extension of Expiration Dates for 13 Body System Listings, 90 Fed. Reg. 43,911 (Sept. 11, 2025)
If the rule is headed for the C.F.R., add a parenthetical noting where it will appear.
Court Cases
A case citation identifies the parties, where the opinion was published, and when the court decided it. The order is case name, volume, reporter abbreviation, starting page, and a parenthetical with the court and year. U.S. Supreme Court decisions appear in the United States Reports (U.S.); federal appellate decisions appear in the Federal Reporter (F., F.2d, F.3d, or F.4th).5Cornell University Law School. Judicial Opinions
Brown v. Board of Education, 347 U.S. 483 (1954)
For Supreme Court cases you do not name the court in the parenthetical because U.S. already identifies it. For lower federal courts, add the court abbreviation: Wilson v. Mar. Overseas Corp., 150 F.3d 1 (1st Cir. 1998).5Cornell University Law School. Judicial Opinions
Pincites
To send the reader to a specific page inside the opinion, add a pinpoint citation after the starting page, separated by a comma. Quoting language on page 495 of Brown looks like this:
Brown v. Board of Education, 347 U.S. 483, 495 (1954)
Parallel Citations for State Cases
Some state courts require citing both the official state reporter and the regional reporter for a case from that state’s courts. This is a parallel citation, and the state reporter comes first. A New York case, for example, might be cited to both the official New York Reports and West’s North Eastern Reporter. In federal court, or when citing a case from another state, the regional reporter alone is usually enough.
The U.S. Constitution
Constitutional citations need only two elements: the name of the constitution and the specific part. Start with U.S. Const., then the article or amendment, section, and clause, with commas between subdivisions.6Cornell University Law School. How to Cite Constitutions, Statutes, and Similar Materials
- Article with clause: U.S. Const. art. III, § 2, cl. 2
- Amendment with section: U.S. Const. amend. XIII, § 2
- Amendment alone: U.S. Const. amend. IV
Nothing is italicized or underlined, and no date is used unless the provision is no longer in effect, such as a repealed amendment.6Cornell University Law School. How to Cite Constitutions, Statutes, and Similar Materials State constitutions follow the same pattern with the state abbreviation in place of U.S., for example N.Y. Const. art. I, § 9, cl. 2.
State Statutes
State statute citations follow the same logic as federal ones — code name, section symbol, section number, and often a date — but the abbreviations and code names vary by state.7Cornell University Law School. Constitutions and Statutes
- Alabama: Ala. Code § 7-1-101 (LexisNexis 2024)
- Colorado: Colo. Rev. Stat. § 1-101 (2024)
- Massachusetts: Mass. Gen. Laws ch. 93A, § 2 (2024)
When a state code is published by a commercial vendor such as LexisNexis or West, formal style calls for identifying the publisher inside the parenthetical along with the date. If the code name includes the word “Annotated,” add Ann. to the abbreviation.7Cornell University Law School. Constitutions and Statutes
Many states also keep a local shorthand their own courts prefer, which may drop the jurisdiction identifier or reorder elements. Arizona courts, for instance, use A.R.S. § 47-1101 rather than the longer national format. If you are filing in a state court, check the local rules; a court may require its own citation format.
Short-Form Citations
Once a source has a full citation on the page, later references can be shortened. The two workhorses are Id. and supra.8Cornell University Law School. Basic Legal Citation
Id. means the same source as the one just cited. If Brown v. Board of Education is in one footnote and you cite it again in the next, write Id. To point to a different page, add it: Id. at 495. Id. works only when the source matches the immediately preceding citation; a single intervening source breaks the chain.
Supra points back to a full citation that appeared earlier but is not the immediately preceding one. It shows up most often for books and articles: “Abraham, supra” tells the reader to look back for the full Abraham citation. Cases do not take supra; instead, use a shortened case name with the volume and reporter, such as Brown, 347 U.S. at 495. Avoid using a common governmental party as the short-form name — in United States v. Wilson, the short form is Wilson, not United States.
Introductory Signals
A signal placed before a citation tells the reader how the cited source relates to your point. The common ones:
- No signal: the source directly states the proposition.
- See: the source supports the point but requires a small inferential step.
- See also: additional support from a different angle, usually after a primary citation.
- E.g.,: the cited source is one of several that could support the proposition.
- Cf.: the source supports by analogy, addressing a different but comparable situation.
Using no signal when see is more accurate overstates how directly the source supports the claim.
Which Citation Guide Governs
The Bluebook, now in its 22nd edition, is the dominant citation guide in American legal practice. Published by the law reviews at Harvard, Yale, Columbia, and the University of Pennsylvania, it is required by most federal courts and law schools.9LII / Legal Information Institute. The Bluebook – Wex – US Law It splits formatting into two tracks: one for court documents and legal memoranda, and one for law review footnotes. The law review track uses small caps and specific typeface conventions that are not needed in a brief or motion.
The main alternative is the ALWD Guide to Legal Citation, now in its seventh edition, developed by legal-writing professionals rather than law review students. ALWD uses a single format regardless of whether the document is a brief or a journal article, and it includes detailed appendixes for state-specific requirements and court-mandated local formats. In practice the two systems produce very similar-looking citations for most common sources, and many courts accept either.
Outside legal-specific writing, general style guides such as the Chicago Manual of Style and APA have their own rules for citing legal materials. They point to the same underlying elements — title, source, section, year — with slightly different formatting.