Letters can be valuable primary sources, but they don't fit standard citation templates. Whether you're citing a published letter collection, archival correspondence, or an email you received, the approach varies significantly.
Feb 3, 2026
By
Joe Pacal, MSc
Search citation styles
TL:DR
Published letters cite like book chapters or anthology pieces. Personal correspondence (letters, emails) is often treated as personal communication—cited in-text but not in the reference list. Archival letters need collection details. Always get permission before citing private correspondence.
Types of Letter Citations
Letters fall into three main categories, each with different citation requirements:
Published letters appear in edited collections, biographies, or scholarly editions. Cite these like other published works.
Archival letters are unpublished documents held in libraries, museums, or private collections. These need detailed location information.
Personal correspondence includes letters or emails you received directly. Most styles treat these as personal communication.
Published Letters
When letters appear in an edited collection, cite the collection:
APA:
Author of Letter. (Year). Title or description of letter. In Editor (Ed.), Title of collection (pp. xx-xx). Publisher.
MLA:
Author of Letter. "Title or First Line of Letter." Title of Collection, edited by Editor Name, Publisher, Year, pp. xx-xx.
Chicago (Note):
Author of Letter to Recipient, Date, in Title of Collection, ed. Editor Name (Place: Publisher, Year), page.
If the letter has a title, use it. If not, describe it: "Letter to Thomas Jefferson, March 15, 1802."
Archival Letters
Unpublished letters in archives require enough detail for readers to locate the document:
Key elements:
Author
Recipient
Date
Description (letter, memo, telegram)
Collection name
Box/folder numbers
Archive name and location
Chicago (common for historical work):
Author to Recipient, Date, Collection Name, Box/Folder, Archive Name, City.
Example:
Jane Addams to Mary Smith, April 12, 1895, Jane Addams Papers, Series 1, Box 3, Folder 7, Swarthmore College Peace Collection, Swarthmore, PA.
APA:
Author. (Year, Month Day). [Letter to Recipient]. Collection Name, Archive Name, Location.
Personal Correspondence
Letters or emails sent directly to you are typically treated as personal communication:
APA: Cite in-text only, not in the reference list:
J. Smith (personal communication, March 15, 2024) confirmed that...
MLA: Similar approach—acknowledge in text, no Works Cited entry needed.
Chicago: Can be cited in a note but typically not in bibliography.
The rationale: readers can't access private correspondence to verify it.
Email as Letters
Email follows personal correspondence rules when it's communication with you:
According to Dr. Martinez (personal communication, January 10, 2024)...
For published or publicly accessible emails (e.g., from email archives, leaked documents, or public records), treat them as published documents with author, date, subject line, and source.
Historical vs. Contemporary Letters
Historical letters are often in archives or published collections. Readers expect you to cite the archival source.
Contemporary letters you received personally are treated as personal communication. Readers can't verify them but trust your representation.
The distinction isn't about age—it's about accessibility. A letter from 1950 in a university archive is citable in a reference list. A letter from your advisor last week typically isn't.
Getting Permission
For unpublished personal correspondence, consider whether you need permission from the letter writer (especially if living), whether the content is sensitive, and whether your use is appropriate.
For archival materials, check the archive's policies on citation and reproduction.
Formatting the Date
Letters are often dated precisely. Include as much date information as you have:
Full date: March 15, 1842
Partial date: March 1842 or Spring 1842
Approximate: ca. 1842 or [1842?]
Unknown: n.d.
Multiple Letters Between Same Parties
If citing multiple letters from the same correspondence, you might group them:
(Adams to Jefferson, various dates, 1812-1815, Adams Family Papers...)
Or cite individually if specific letters matter to your argument.
Letters in Digital Archives
Many archives have digitized letters with stable URLs:
Author to Recipient, Date, Collection Name, Archive, URL.
Include the URL if it provides stable access. If the archive requires login or has unstable links, cite the physical collection details instead.
The exact formatting for letter citations depends on your required citation style. Check the specific guide for your discipline below.
