The John B. Coyle papers consist of two items, a typescript of a personal diary, which covers the years 1856 to 1882, and a photocopy of the typescript diary pages for the years 1856 to 1860.

The personal diary is a collection of typescript pages of a personal diary kept by John B. Coyle between January 1, 1859 and December 21, 1882. The years 1857, 1877, and 1880 are not represented. The typescript was executed in 1958 by a great-granddaughter of Coyle (possibly Emily L. Graves) living in Waltham, Massachusetts, as indicated by an introductory letter to the material, which is signed "Sis." Parenthetical material that appears to be the transcriber's interpretation of annotations placed by the author is also included. The transcriber indicated that many annotations were not transcribed, particularly those containing financial information.

The bulk of the diary entries are typical of most diarists: comments about travel, weather, and health matters, with few details beyond that. Most business comments are very sketchy and lack detail. In many entries, insufficient information is presented to determine the location referenced. One of Coyle's duties, at least early in the time period represented, was to oversee construction of vessels, largely built in New York, by the Englis (or Euglis) Company. His comments in this regard are usually related to how the weather affected the progress of construction.