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  • Writer's pictureGordon Thorsby

A Michigan Man in the 123rd Illinois Mounted Infantry

by Gordon Thorsby

Soldier in 123rd IL. notice the two pistols (William Perisho, Co. G) he died of disease 1863.

Yes, Tom is my ancestor.

Thomas T. Thorsby was born in Yorkshire, England 7/21/1820 and his family arrived to New Jersey in 1827. In 1853, he, his wife Margaret (Cornford), and one child were living in Birch Run, Michigan when one of the harshest winters on record forced them to seek warmer farming climate in Southern Illinois. A war raged in neighboring state Kentucky so Tom enlisted on September 6, 1862 in Co. D, 123rd Illinois, as Private, and at a not young age of 42. His primary motivation for joining might have been money. Tom Thorsby was a poor man with a wife and four young children to feed.

Six companies of the 123rd mustered were from Coles County where its training camp was established at Mattoon, just two miles away from Tom’s home. Colonel James Monroe (killed in 1863) was its first commander. (Ulysses S. Grant organized his first command at Mattoon.). Within two weeks, the regiment was off to Louisville to defend from Bragg’s invasion.

The regiment was raw. They could walk but they couldn’t march or form a line. The results from their first action at Perrysville n October 8 demonstrated their lack of training where 36 men were killed and 180 wounded. Perryville would be the 123rd’s worst day of the war.

Continued fighting and campaigning cut into the regiment during the next months when second in command Lt. Col James Connelly wrote this excerpt home April 20, 1863, “I am in no hurry to get into any more battles, for I think we have done our full share so far. We have been under fire 15 times, we are cut down in 8 months service from 962 men to about 460, 200 of that loss being in battle and skirmish, so that all things considered I don’t care to fight any more…”

In April, the 123rd was converted to Mounted Infantry and it fought with four other regiments that became "Wilder's Lightning Brigade." The farms of Tennessee had plenty of mounts but the Union army had none. Within days, the regiment became mounted by conscripting horses from the area. The Christopher Spencer repeating long rifle, purchased at their personal expense, became their firearm. The regiment moved like cavalry as it could ride 20-25 miles on an average day. It fought like infantry because when they got to where they

needed to be, they dismounted and could take on forces three times their size. The first demonstration was at Hoover’s Gap in the Tullahoma Campaign in June of 1863.

Union Infantry were slugging it out on muddy roads and steep hills so it was up to the mobile infantry advanced to seize the gap before Confederate forces could seal it. Orders were not obeyed but the gap was more important. In position, the brigade found itself under assault from Brig. Gen. Bushrod Johnson’s infantry division. Private John N. Smith of Company D recalled, “[the] rebels charged the battery with deafening yells but were met with a sheet of lead from Spencer rifles--they fell back in confusion-now seeming to realize they were not fighting cavalry.”

Members of Co. E 123rd

Lt. Col. Connelly wrote in his official report, “the enemy opened on us a terrific fire of shot and shell from five different points, and their masses of infantry, with flags flying, moved out of the woods on our right in splendid style; there were three or four times our number already in sight.”

Further, he added, “they "reckoned without their host," they didn't know we had the "Spencers," and their charging yell was answered by another terrible volley, and another and another without cessation, until the poor regiment was literally cut to pieces, and but few men of that 20th Tennessee that attempted the charge will ever charge again.” When fighting with Spencers, regiments performed as brigades and the Lightning Brigade fought like a division.

On September 18, the 123rd was part of the force blocking Alexander’s Bridge against W.H.T

Walker’s Corps. On the 19th, it was part of crumpling the advancing lines of Gregg’s infantry in Viniard Field. On the 20th, when Sheridan’s division began to give way, the regiment stayed behind in a delaying action during the retreat.

The 123rd’s next major fighting role was Wilson’s Selma Campaign in mid-April 1865, where it fought dismounted assaulting Forrest’s breastworks. Even though the war was ending, the regiment fought hard suffering 8 killed and over 50 wounded.

Tom Thorsby was in the line during the entire 21/2 years. He was paid off and discharged July 11, 1865, now a 45 year old man. He returned to the family in Illinois. Tom moved the family back to Birch Run in 1865 and he started farming again. Tom and Margaret watched their five kids grow up in Michigan. He managed to live until October 22, 1900, at the age of 80. (He mustered out as Corporal.) Through his fortitude, his descendants carried on the name. They became carpenters, undertakers, soldiers in WW1 and WWII, naval aviators and even actors.

Thomas Thorsby at app. age 60.

Note: Not in my wildest dreams could I endure what this guy did; he did not find himself dead, discharged, or in a convalescent battalion. One tough dude.


Tullahoma, by Powell, David A. And Wittenberg, Eric J., Savas Beatie, 2020.

Yankee Blitzkrieg, by Jones, James Pickett, University Press of Kentucky, 1976.

Perryville Battling for the Bluegrass, Kolakowski, Christopher L., The History Press, Charleston, SC 2009.

Official Records in the War of the Rebellion, PAGE 459-50 [CHAP. XIII., [Series I. Vol. 30. Part I, Reports. Serial No. 50.]

James Austin Connolly (Major, 123rd Illinois), Three Years in the Army of the Cumberland: The Letters and Diary of Major James A. Connolly, ed. Paul M. Angle (1928; reprint, Indiana University Press, 1996),

The American Descendants of Thomas Cornford- 1762,

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