The 105th Illinois Infantry Regiment was an infantry regiment in the Union Army during the American Civil War. The regiment was made up of volunteers, primarily from the Illinois counties of DeKalb and DuPage but other counties were represented as well. The 105th Regiment served from 1862 through the end of the war in 1865.

The 105th was formed in response to President Lincoln's July 1862 Proclamation 121 which requested 300,000 volunteers from throughout the Union to serve for three years.

The regiment consisted of ten companies of approximately 100 men each. Six of the companies were made up of men from DeKalb County and four companies came mostly from DuPage County.^[1] The regiment was mustered at Fort Dixon in Dixon, Illinois on September 2, 1862. It moved from Dixon to Camp Douglas in Chicago on September 8, 1862.

The regiment, commanded by Colonel Daniel Dustin, was attached to the 40th Brigade commanded by General William T. Ward. The 40th Brigade was a part of 12th Division in the Army of the Ohio.

• Sept. 1862 - Nov. 1862: Ward's Brigade, Dumont's 12th Division, Army of the Ohio
• Nov. 1862 - June 1863: Ward's Brigade, Post of Gallatin, Tenn., Dept. of the Cumberland
• June 1863 - Aug. 1863: 2nd Brigade, 3rd Division, Reserve Corps, Dept. of the Cumberland
• Aug. 1863 - Jan. 1864: Ward's Brigade, Post of Nashville, Tenn., Dept. of the Cumberland
• Jan. 1864 - Apr. 1864: 1st Brigade, 1st Division, 11th Army Corps, Army of the Cumberland,
• Apr. 1864 - June 1865: 1st Brigade, 3rd Division, 20th Army Corps, Army of the Cumberland, and Army of Georgia to June, 1865.

^[2]

• BEGGS, George W (Asst. Surg.)
• BROWN, Henry D (Major)
• CHANDLER, David D (Adjutant)
• CHAPMAN, Daniel (Chaplain)
• CRAWFORD, Levi P (Chaplain)
• DUSTIN, Daniel (Colonel)
• DUTTON, Everell F (Lt. Colonel, Major)
• PHILLIPS, William N (Adjutant)
• POTTER, Horace S (Surgeon)
• VALLETTE, Henry F (Lt. Colonel)
• WATERMAN, Alfred (Asst. Surg., Surgeon)
• WELLS, Timothy (Quartermaster)

The 105th Illinois Infantry was organized at Dixon, Illinois, and mustered in for three years of service on September 2, 1862, under the command of Colonel Daniel Dustin. It was recruited in DeKalb and DuPage counties.

The regiment was attached to Ward's Brigade, Dumont's 12th Division, Army of the Ohio, to November 1862. Ward's Brigade, Post of Gallatin, Tennessee, Department of the Cumberland, to June 1863. 2nd Brigade, 3rd Division, Reserve Corps, Department of the Cumberland, to August 1863. Ward's Brigade, Post of Nashville, Tennessee, Department of the Cumberland, to January 1864. 1st Brigade, 1st Division, XI Corps, Army of the Cumberland, to April 1864. 1st Brigade, 3rd Division, XX Corps, Army of the Cumberland and Army of Georgia to June 1865.

The 105th Illinois Infantry mustered out of service on June 7, 1865, and discharged at Chicago, Illinois, on July 17, 1865.

The regiment lost a total of 238 men during service; 2 officers and 49 enlisted men killed or mortally wounded, 187 enlisted men died of disease.

• List of Illinois Civil War units

• Cram, George Franklin. Soldiering with Sherman: Civil War Letters of George F. Cram (DeKalb, IL: Northern Illinois University Press), 2000. ISBN 0-87580-261-3
• Dyer, Frederick H. A Compendium of the War of the Rebellion (Des Moines, IA: Dyer Pub. Co.), 1908.
• Strong, Robert Hale (1961). Halsey, Ashley (ed.). A Yankee Private's Civil War. Chicago: Henry Regnery Company. LCCN 61-10744. OCLC 1058411.
• This article contains text from a text now in the public domain: Dyer, Frederick H. (1908). A Compendium of the War of the Rebellion. Des Moines, IA: Dyer Publishing Co.

• Roster of the 105th Illinois Infantry