The Herbert Deuel Civil War Collection contains two of Deuel's Civil War diaries (1864-1866), artifacts from battlefield sites including Bull Run and Petersburg, and printed ephemera.

The diaries in this collection begin an unknown amount of time after Deuel has been with the 17^th Regiment, Michigan Infantry. On several occasions, he notes a date as the anniversary of an event and it seems he was with the regiment at least as early as 1863. The first diary (March-November 1864) provides some detail of his experiences surrounding the Battles of the Wilderness and Spottsylvania. It was during the latter he was wounded. The remainder of the first diary details Deuel's experiences in the hospital, on furlough in Michigan, and his return to Philadelphia. The last pages contain plant pressings from several battlefield sites. From this point on, there is no further mention of the war, except for occasional news items (the fall of Richmond and Lincoln's assassination, for example). Instead, the second diary (November 1864-January 1866) describes Deuel's day-to-day life as a clerk in the hospital, his religious activities (attending church and bible classes), and who he visited.

Artifacts in this collection include used and unused bullets, one of which is marked "Union bullet Bull Run, Va 1864"; arrowheads; several buttons; and a leather pouch. The collection also contains a small drawing of Stirling Castle in Scotland, and remnants of a flag labeled "Piece of Rebel Genl. Malone's (most likely Mahone) Division Flag Petersburg, Va 1865."

The small group of printed ephemera contains a news-clipping about the removal of Confederate prisoners from Washington, DC; "The Soldiers' Guide to Philadelphia"; a poem, "Hand in Hand with Angels"; and two passes allowing Deuel to be absent from St. Mary's hospital in Detroit (1864).