This collection contains the diary of Charles O. Poland, a private in Company B, 142nd Ohio Infantry (National Guard) during the Civil War. The diary's entries commence on June 15, 1864, with Knox already in the rifle pits before Petersburg. He writes of being detailed to destroy Confederate breastworks, erect fortifications, and fell trees as battles raged nearby. Elsewhere he mentions having seen generals Grant and Burnside, the gunboats on the James River, the discovery of a cache of buried silver and gold by a New York regiment while hunting for fishing worms, and the trading of hardtack for tobacco between the lines. Throughout the diary, Poland notes many days on picket, and the state of the fighting around Petersburg. On July 20, Poland developed a fever, and the final four entries, concluding with July 31, are devoted to the condition of his health.

Also within the diary are a few entries regarding pre- and post-war personal financial transactions; the diary is accompanied by two 1855 documents certifying Poland as qualified to teach in Knox and Morrow counties.