Chicago style allows you some leeway in deciding whether to set off a long quotation or run it into your text. For emphasis, you may want to set off a quotation of more than four or five lines of text; almost certainly you should set off quotations of ten lines or more.

To set off a quotation, indent it one-half inch from the left margin and use the normal right margin. Double-space the indented quotation.

Long quotations should be introduced by an informative sentence, usually followed by a colon. Quotation marks are not necessary because the indented format tells readers that the words are taken directly from the source.

In a letter home, Confederate officer Achilles V. Clark recounted what happened at Fort Pillow:

Words cannot describe the scene. The poor deluded negroes would run up to our men fall upon their knees and with uplifted hands scream for mercy but they were ordered to their feet and then shot down. The whitte [sic] men fared but little better. . . . I with several others tried to stop the butchery and at one time had partially succeeded[,] but Gen. Forrest ordered them shot down like dogs, and the carnage continued.⁸