Ashley left two documents describing the events of 1825: One is what appears to be his field diary, containing daily entries. The other is a letter to Gen. Atkinson written after Ashley's return that fall, and contains a narrative of his 1825 season in the Rockies. These two documents are mostly consistent, although the narrative appears to have been written from memory because in some cases, details are different from those recorded in the contemporaneous diary.
The diary was kept from March 25 to June 27, 1825. The diary commences on the Platte, just east of the continental divide. It describes the journey to the Green River and the division of the trapping party there. It also details Ashley's trip down the Green River in bullboats, and ends just a few days before Ashley's parties met on the Henry's Fork for the first Rocky Mountain Rendezvous.
The narrative covers a longer period of time, from the time he left Ft. Atkinson on November 3, 1824 until he reached the Yellowstone below Big Horn Mountain on the 7th day of August, 1825. From there he proceeded downriver in boats with his rich cargo of furs, to the settlements.
Ashley's Narrative was published in:
The Ashley-Smith explorations and the discovery of a central route to the Pacific, 1822-1829, with the original journals, by Harrison Clifford Dale, Cleveland, The Arthur H. Clark company, 1918.