The Chicago style essay format is most widely used in the realm of academic writing, particularly in the humanities field. This style is often compared to the American Psychological Association (APA) format, since both require a specific formatting of text and bibliography. However, the Chicago style is more commonly used when citing primary sources such as books or journals, as opposed to APA which typically references secondary sources.

The main distinctive features of this style include the use of footnotes or endnotes along with a bibliography page at the end of the essay. The bibliography page should include all sources referenced within the text, including both books, journals and websites. Similarly, within the body of the text, any reference to an outside source should include a footnote or endnote that provides more information about the source.

The Chicago style also requires that all text be double-spaced and that a specific font size (12 pt) is used. The title page should be centered and should feature the title of the essay and the author's name. An abstract may also be included at the beginning of the essay, although it is not necessary.

In addition, the Chicago style requires that any quote longer than 5 lines be formatted in a block quotation. Block quotations should be indented from the left margin and should lack any quotation marks. The footnotes should also include full information about the source including the author's name, title of the source and publication date.

Overall, the Chicago style is often used in academic writing due to its flexibility and focus on primary sources. Adhering to these guidelines allows authors to properly credit their sources while still providing a standardized format for readers.