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Chicago 17: Introduction to Chicago Style (17th ed.)

Learn how to format your papers and cite resources in Chicago 17th format.

Chicago Style

Chicago (CMOS) style is a citation format usually used in the humanities, history, the arts, etc. It includes different versions for notes, shortened notes, and bibliographic entries.

  • This guide is specific to the Notes-Bibliography style. While footnotes are emphasized in this guide, CMOS's Notes-Bibliography style also allows for endnotes. Notes-Bibliography style is what most of your history professors prefer, but you will need to ask to make sure.
  • Your professor may prefer that you use Author-Date style. If so, this guide doesn't include the information you need.

Chicago Style Resources

The Chicago Manual of Style is the official guide to Chicago format. You can also visit the Chicago Manual of Style Quick Guide for official guidance.

Notes-Bibliography System Overview

In the notes-bibliography system, each in-text reference is denoted by a number that corresponds to a footnote.

  • When it's time to cite a source within the text of your paper, you'll insert a footnote outside of the period or other punctuation using your word processor.
  • A superscript 1 will appear after the punctuation mark, and you will be taken to the footer of the page which will also show a 1. The superscript 1 in the text alerts your reader to look for the 1 on the bottom of the page for more information.

Superscript 1

From Purdue OWL's "CMOS NB Sample Paper."

  • In the footer, add a period after the number, and create your footnote.
    • The first line of a footnote is indented .5” from the left.
    • Subsequent lines of a footnote are flush left.
    • Footnotes are single-spaced within a note.
    • Double-space between footnotes.
  • Each subsequent note within your text will follow in numerical order throughout your paper. Even if you insert a note in between notes, for example, the software you are using will adjust.


From Purdue OWL's "CMOS NB Sample Paper."

In the notes-bibliography system, the page at the end of your paper where you will list all of your citations should be titled Bibliography.

  • Bibliographies should be organized in alphabetical order by the first letter in the first word of each entry.
  • Subsequent lines of an entry have a hanging indent.
  • Write out the names of the first 3 authors.
  • If there are 4 to 10 authors, write out the names of each author in the bibliography entry, but use First Author Name et al. in the footnote.
  • Use DOIs instead of URLs if possible.
  • Make DOIs active.

Bibliography Sample

From Purdue OWL's "CMOS NB Sample Paper."


Special thanks to the following libraries for permitting the Merced College Library to adapt their Chicago 17th ed. guides.