Three holograph diaries dated Sep 20, 1853-Aug 27, 1854; Sept 1, 1854-Aug 26, 1856; Sep 1, 1856-Mar 6, 1857; and Mar 7-Oct 18, 1857, documenting John G. Coy's gold mining activities in Grass Valley (Nevada County), Prairie City (Sacramento County), Marysville (Yuba County), Portuguese Flat (Shasta County), Ione Valley (Amador County) and other Northern California locations including sites in Sierra County. The earliest diary consists of eight unbound pages; the subsequent diaries are in the form of pocket diaries. Entries include descriptions of Coy's movement from one area to another; his mining activities, including work performed and daily and weekly income; his interactions with miners, friends and acquaintances; and his family and business correspondence. Coy's entry of Sep 24, 1855 describes an Indian "fandango" in Ione Valley, including the dress, music, and dance of members of unnamed tribes.
Entries at the back of each volume contain personal accounts for the period covered in the diary; the diaries dated 1856-57 and 1857 also contain accounting entries relating to the Coy & Hacker and Coy, Hacker & Baxter Companies. The diary dated 1856-57 contains a key to the shorthand marks Coy uses in the diaries. Accompanied by an undated cabinet photograph of Coy taken by G. I. Wilkins, Artistic Photographer, Fort Collins, Colorado.