The major portion of the collection consists of correspondence, 1857-1892. Fifteen letters fall in the years 1857-1860. Of these, most were written by Wheeler as a student in schools at Platteville and Meriden; two relate to unsuccessful attempts to secure for him an appointment to one of the United States service academies. About 130 letters cover Wheeler's Civil War service in the Second Wisconsin Infantry and in the Quartermaster's Department at Little Rock. Cornelius wrote to his parents and his younger brother Charlie quite frequently and regularly. Many of the letters are descriptive; many contain frank comments on officers and wartime events. Wheeler was not an abolitionist; he deplored the use of African-American troops by the North, and suggested that Lincoln had been misled in issuing the Emancipation Proclamation. He did not hesitate to sympathize with and applaud one relative who intended to desert to Canada if he was drafted. The 17 final letters fall into two periods: 1867-1868, when Wheeler was becoming established in Portage; and 1891-1892, when he sought the appointment to superintend the Soldiers' Home. One letter, dated January 6, 1892, was written by Congressman John L. Mitchell expressing his approval of Wheeler's appointment.
The collection contains a handwritten manuscript “Sketch of the Services of Company I, Second Regiment, Volunteer Infantry, 1861-1864,” written by Cornelius Wheeler. This manuscript appears to have been under preparation for publication in installments, but it seems never to have been completed. The first portions are in relatively finished form, but later parts are sometimes fragmentary and often exist in more than one draft. From the letterheads on which some pages of the manuscript are written it is evident that Wheeler was working on this project after 1892 when he went to the Soldiers' Home. There is also a carbon typescript of the major portion of the manuscript, which was prepared by the former owner of the collection, Mrs. Chester Colley. Accompanying the history are descriptive rolls containing copies of the records of the men serving in Company I. These records are very similar to and may have been copies from the official Descriptive Rolls compiled by the Wisconsin Adjutant-General which are now in the Wisconsin State Archives at the Historical Society.
Included with the manuscripts is one folder of newspaper clippings about Wheeler and an obituary leaflet about his life. The clippings relate primarily to his governorship of the Soldiers' Home.
