The Civil War Collection is an "artificial" collection of materials that were donated by or acquired from a variety of unrelated sources but have been organized together by subject matter. The materials in this collection have been digitized and are available online to on-site researchers and to users affiliated with subscribing institutions via EBSCOhost.

The collection has been arranged into folders by document type. The majority of documents in the collection were generated by individuals or departments within the Union. Correspondence includes pre-war correspondence of figures who later participated in the Civil War; military and official correspondence; and personal correspondence of soldiers writing to relatives and loved ones. There are also several envelopes printed with soldier ballots for the presidential election of 1864.

The collection also includes a variety of Union military documents, including battle and other official reports; military orders; certificates of enlistment, discharge and pension; safe-conduct passes; court-martial papers; and requisitions, bills and receipts (including bills of lading for shipped cotton). Other official documents include oaths of allegiance to the U.S.Government and presidential pardons signed by Andrew Johnson.

There is one folder of Confederate material. It includes military correspondence (most notably, a manuscript copy of Lieutenant Hardee's letter refusing Sherman's demand to surrender Savannah), an oath of allegiance to the Confederate States of America, safe-conduct passes, reports of deserters, receipts and vouchers, and Confederate currency. There is also a folder of material relating to slaves, including an 1860 mortgage document listing all the slaves on the plantation of John Williams, receipts for slaves supplied to labor for the Confederate army, and a certificate dated August 2, 1862, freeing a slave in South Carolina.

Several folders of legal papers consist primarily of claims brought after the war for damage caused to property (including cotton) in the Confederate states by the Union army. Many of the claimants were represented by Thomas J. Durant, a New Orleans lawyer who played a prominent role in reconstruction efforts in Louisiana immediately following the war.

Other post-war materials include personal reminiscences, documents relating to Civil War memorials, and biographical sketches of soldiers solicited by Frank Moore for his Rebellion Record. Also included are several 19th century catalogs of Civil War-related material.