The United States Civil War Collection contains manuscript and printed materials dating from the Civil War era, as well as later items about the war. These materials include correspondence, speeches, pamphlets, and newspapers. The bulk of the material dates from 1861 to 1865, and both Northern and Southern perspectives are represented. Highlights of the collection include an 1823 bill of sale for a slave, a facsimile copy of President Abraham Lincoln's 1863 letter to Major General Joseph Hooker, placing him in command of the Army of the Potomac, and an 1864 diary. Also included is information pertaining to several persons of interest such as Henry Clay, Victor Hugo, Benson Lossing, James Monroe, and Henry Jackson Van Dyke. The collection is divided into ten series: Manuscripts, Printed Correspondence, Speeches and Sermons, Speeches from the House of Representatives, Speeches from the US Senate, General Publications, Legal Materials, Medical, Plates and Portraits, and Ephemera. Each series is arranged alphabetically.

The Manuscripts series is comprised of several documents dating from 1823 to 1865. Included are personal letters regarding daily life, military experience and business, as well as Southern diaries containing Confederate poetry. Items of interest include an 1823 bill of sale of a slave, draft deferment documentation, and a facsimile copy of President Abraham Lincoln's 1863 letter to Major General Joseph Hooker, placing him in command of the Army of the Potomac.

The Printed Correspondence Series is composed mostly of letters from both Northern and Southern perspectives. Much of the documentation includes editorials and articles arguing for or against the institution of slavery, and several prominent authors from the era are featured. Included in this series is an essay by Victor Hugo titled "Letters on American Slavery" in which he fervently denounces the practice. Also included are essays about post-war Reconstruction, as well as reports relating to US Foreign policy from 1861 to 1865.

The Speeches and Sermons series dates from 1811 to 1868 and documents several verbal accounts of slavery from the North and South. Other topics covered include US foreign relations, Reconstruction, and the Fugitive Slave Law. Of particular interest are documents contrasting the doctrines of the Democratic and Abolitionist Parties.

The Speeches from the House of Representatives series dates from 1835 to 1865 and contains mostly pro-Northern materials. The majority of the documents attack slavery on moral grounds, and several essays criticize the economic and ethical foundations of the institution. Highlights include an essay by Jim Ashley titled "The Barbarism of Slavery," as well as a treatise by I.N. Arnold titled "Slavery: The Cause of the War and All Its Evils."

The Speeches from the Senate series dates from 1850 to 1868. Both Northern and Southern perspectives are presented. Highlights include an essay by Henry Clay titled "Resolutions on the Issue of Slavery," as well as a resolution preparing to retrocede the Southern courts.

The General Publications series begins in 1835 and also includes documents published during the 1970’s about the Civil War. Much of this material was written after the conflict, and includes several comprehensive historical accounts. Items featured are catalogues of Civil War Battles, a chronological history of the Civil War, and photographs published in 1979. Also included are several academic essays about Civil War History, as well as writings pertaining to US foreign Policy during the mid to late nineteenth century.

The Legal Materials series dates from 1856 to 1865. Highlights of the series are a report of the decisions of the Supreme Court during the Dred Scott case, and an essay by Tatlow Jackson titled "Martial Law: What it is and who can declare it."

The Medical series dates from 1861 to 1865, and focuses mostly on the sanitary conditions of the battlefield. The series is comprised of surveys, letters, and outlines pertaining to the hygienic, medical, and surgical procedures during the war. Highlights include a piece by Joshua Nicholas Speed titled "A letter on the sanitary conditions of the troops in Boston," as well as the letters of Dr. William Hanchett titled "Illinois physician and the Civil War Draft."  Other items of interest are a report on Government hospitals and Agencies, as well as documents recounting the operations of the US Sanitary Commission.

The Plates and Portraits series is comprised mostly of photographs and prints that were published during the twentieth century. Featured items are prints illustrating Civil War battle scenes, officer prints, portraits and photographs, national military aerial views, and twenty re-prints of President Lincoln. The only dated materials are from 1910 and 1946.

The Ephemera series dates from 1856 to 1875.  Materials include a Civil War issue of Americana Press, newspaper reproductions, scrapbooks, and Southern currency. Other items of interest include original confederate poetry and postage stamps, as well as selected poems about General Ulysses S. Grant.