Everything I've read about John Morgan's service in the Civil War places him in the 123rd Illinois Infantry. I just saw a source the other day which was a bit confusing. This is a record called "Veterans with Federal Service Buried in Utah, Territorial to 1966," and it lists his enlistment as December 14, 1863 in Rush Co., Indiana, and his regiment as Co E, 123rd Inf.
I would have assumed that this record was accurate — why wouldn't it be? — but this is a case of "don't believe everything you read." The John Morgan who enlisted in Rush County on December 14, 1863, was a John F. Morgan from Richland, Indiana, who belonged to the 123rd Infantry Regiment Indiana, Company E. (See the company roster.)
Our John Morgan served in the 123rd Infantry Regiment of Illinois, Company I.
Here is his entry in the company record. It is the last one on the top page. It shows that he was from Mattoon, Coles, Illinois, that he enlisted on August 1, 1862, that he was mustered in on September 6, 1862, and that he mustered out on June 28, 1865 as a sergeant.
Reece, Jasper N., and Elliott, Isaac Hughes, 1837-1922. Report of the Adjutant General of the State of Illinois, Vol. 6. Springfield, Illinois:Journal Company, Printers and Binders, 1900, 412. (Link.)
Here is another record I saw, John Morgan's entry in the 1890 Census of Union Veterans and Widows of the Civil War (Utah).
The reason I looked up these service records is because I am a Boy Scout Merit Badge Counselor, and I was doing the Citizenship in the Nation merit badge with my two sons yesterday. As part of one of the required discussions, I decided to pull out my biography of John Morgan and read them from some of his letters including the following excerpts:
Tell Pa that I wish I was home to help him but as long as there is an armed foe to my country at large, I will be found in the ranks of the Patriot army. It is getting late and I must close. (Letter to his mother, as edited in The Life and Ministry of John Morgan, 17.)
It makes me a little riley to hear of good staunch administration men turning from their allegiance to their Government and supporting on of the most God forsaken projects (as the present Peace Party claims to be) that was ever invented.
Were it possible I would wish that Lincoln could assume the power of a dictator for 12 months and would hang every man that dared utter one word in favor of the rebellion or peace.
Congress and Northern Legislatures and northern traitors are doing more for the cause of the Rebellion than all the Southern Army: they are discouraging the Federal Army and encouraging the Rebels as much as lay in their power.
We of the army are in for nothing but the subjugation or annihilation of the South and if we cannot accomplish it in three years we can in six but that it can be done we are satisfied and that we are the Army that can do it we are also satisfied.
I am in as good health as I ever was in my life. My back is as strong as all outdoors. I can march 25 miles in a day—drink 2 pints of coffee; eat some fat pork and wrap myself in a blanket and sleep sounder than I ever could at home. (Letter to his father, also edited in The Life and Ministry, 11.)For more information on John Morgan's Civil War service, see the military posts listed in Important John Morgan Posts, and the information on Bessie's blog including John Hamilton Morgan (1842-1894) and his son, John Hamilton Morgan (1894-1982).