138th Regiment, Illinois Infantry (100 days, 1864)
The 138th regiment, Illinois Infantry ( 100 days, 1864) was organized at Camp Wood, Quincy, Illinois, and mustered in for 100 days June 21, 1864. It mustered out October 14, 1864. 
Companies in this Regiment with County of Origin
Men often enlisted in a company recruited in the counties where they lived though not always. After many battles, companies might be combined because so many men were killed or wounded. However if you are unsure which company your ancestor was in, try the company recruited in his county first.
The following counties of origin are taken from the Adjutant General's Report, found on the Illinois Civil War Rosters web site. Roster pages are from the same report found on the Internet Archives web site. The rosters show the men who served in each regiment, their residences, dates of enlistment and mustering out, and other remarks.
- Company A - many men from Warren County - Warren County web site -
- Company B - many men from Knox County - Knox County web site -
- Company C - many men from Warren County - Warren County web site -
- Company D - many men from Henderson County - Henderson County web site -
- Company E - many men from Knox County - Knox County web site -
- Company F - many men from Livingston County - Livingston County web site -
- Company G - many men from Kankakee and Will counties - Kankakee and Will county web sites -
- Company H - many men from Grundy County - Grundy County web site -
- Company I - many men from LaSalle County - LaSalle County web site -
- Company K - many men from Marshall and LaSalle counties - Marshall and LaSalle county web sites -
- Unassigned Recruits
- Civil War Soldiers and Sailors System, (accessed 30 Dec. 2010) can be searched by soldier's name or by regiment; includes regimental rosters and additional history of the regiment.
- Organized at Mattoon, Illinois, and mustered in for 100 days June 6, 1864. Mustered out September 28, 1864.