In legal citations, supra and infra are Latin shorthand that point the reader to a source or discussion located elsewhere in the same document. Supra means “above” and sends you backward to a full citation that already appeared earlier. Infra means “below” and sends you forward to something the writer will get to later. Both show up constantly in law review articles, briefs, and academic legal writing because repeating a complete citation every time the same authority comes up would clutter the page.
How Supra Works
When a legal writer first mentions a book, article, report, or similar source, they give the complete citation: author, title, volume, pages, year. After that, they use supra plus just enough information to send you back to the original.
A typical reference in a footnote looks like this: Ackerman, supra note 5, at 1425. That tells you the source is by someone named Ackerman, the full citation lives in footnote 5, and the specific page is 1425. The word “at” followed by a number always marks a pinpoint page. If no page is specified, the writer is referring to the source generally.
Supra is always italicized. Under Bluebook Rule 4.2, it can be used for books, law review articles, reports, pamphlets, legislative hearings, court filings, treaties, unpublished materials, and similar secondary or nonperiodic sources.1The Bluebook. 4.2 Supra and Hereinafter It appears far more often in scholarly writing than in courtroom filings, though you’ll see it in both.
How Infra Works
Infra runs in the opposite direction. It tells the reader that the full discussion, citation, or analysis appears later in the same document. Writers use it when they want to mention a concept early without stopping to explain it. A brief might introduce a legal theory in its opening section and add “see infra Section III” so the reader knows the supporting detail is coming.
Under Bluebook Rule 3.5, infra is used for internal cross-references to material appearing later in the same piece.2The Bluebook Online. 3.5 Internal Cross-References A forward reference might read: “see infra notes 123–127 and accompanying text.” Where supra creates a trail backward, infra acts as a promise that the writer will cover the point.
Reading the Pieces of a Shorthand Citation
Each part of a supra or infra reference carries specific information. A supra citation generally contains the author’s last name (or a shortened title for works without a named author), the word supra, “note” plus the footnote number where the full citation first appeared, and optionally “at” plus a pinpoint page. Breaking down Levinson, supra note 1, at 25: the source is by Levinson, the full citation sits in footnote 1, and the pinpoint is page 25.
An infra citation is usually simpler because it just references a section, part, or note coming later: “see infra Part II.B” or “see infra note 34.” No author name is needed, because the point isn’t to identify a previously cited source but to flag where in the current document the reader should look next.
The word “note” always means a footnote or endnote. “At” always means a specific page. “At 302–05” directs you to a page range within the cited source. These conventions are consistent across legal writing, so once you recognize the pattern any shorthand citation becomes easy to decode.
When Supra Cannot Be Used
This is where most citation mistakes happen. Supra cannot be used as a short form for cases, statutes, constitutions, legislative materials (other than hearings), restatements, model codes, or regulations.1The Bluebook. 4.2 Supra and Hereinafter The only exception is extraordinary circumstances, such as when the authority’s name is extremely long.
If you need to cite a case again after the full citation, use a shortened case name. For a statute, repeat the abbreviated statutory citation. The reasoning is that primary legal authorities have their own well-established short forms, so supra would create confusion rather than eliminate it. Secondary sources like books, journal articles, and reports lack standardized short forms of their own, which is where supra does its real work.
Supra Versus Id.
The other shorthand you’ll see constantly is id., and mixing it up with supra is one of the easiest mistakes to make. Id. means “the same thing I just cited.” Supra means “something I cited earlier, but not immediately before this.”
Under Bluebook Rule 4.1, id. is used only when referring to the immediately preceding authority, and only when that preceding citation contains a single source.3The Bluebook Online. 4.1 Id. If the footnote directly above cited three different sources, id. would be ambiguous because the reader wouldn’t know which one you mean. In that situation, you use supra (for eligible source types) or a short-form case citation instead.
Rule 4.2 directs writers to use supra to refer to a previously cited authority “unless id. would be more appropriate,” which means id. takes priority whenever it’s available.1The Bluebook. 4.2 Supra and Hereinafter If footnote 47 cites a single article and footnote 48 wants the same article, footnote 48 uses id. If footnote 52 needs that article again after other citations have appeared in between, footnote 52 uses supra with the author’s name and the original footnote number.
Hereinafter as a Companion
One related shorthand worth knowing is “hereinafter,” which creates a custom nickname for a source with an unwieldy title. The first time the source appears in full, the writer assigns a shorter label in brackets: International Covenant on Civil and Political Rights, Dec. 16, 1966 [hereinafter ICCPR]. Every later citation then uses the nickname with supra: ICCPR, supra note 3.1The Bluebook. 4.2 Supra and Hereinafter
Unlike supra and infra, hereinafter is not italicized. You’ll rarely see it in short briefs, but in long law review articles that cite the same treaty or multi-volume report dozens of times, it saves significant space and keeps the footnotes readable.
Finding the Source Behind the Reference
When you hit a supra reference, travel backward in the document to the footnote number indicated. If the citation says supra note 12, go back to footnote 12, where you’ll find the complete citation with the full title, publisher, year, and other details. In digital documents, footnote numbers are often hyperlinked, so clicking the number jumps you straight there. If there’s no hyperlink, use your PDF viewer’s search function to find “12.” followed by the author’s name.
For infra, you move forward. If the reference says infra Section IV, look for a heading labeled “Section IV” or “Part IV” later in the document. If it says infra note 88, scroll down to footnote 88. The goal is reaching the place where the writer addresses the topic in full, so you can evaluate the source and the argument built on it.