12th Regiment, Michigan Infantry
The 12th Regiment, Michigan Infantry was organized at Niles, Dowagiac and Buchanan, Michigan, December 9, 1861, to March 1, 1862. It was mustered in March 5, 1862. The Regiment assembled at Camden and mustered out February 15, 1866. 
For a history of this regiment see Michigan Regimental Histories which gives a brief history, places served, battles fought, commanders and company rosters.
For more information on the history of this unit, see:
- The Civil War Archive section, 12th Regiment Infantry, (accessed 20 July 2012).
- The Wikipedia article, 12th Michigan Volunteer Infantry Regiment, (accessed 13 July 2012).
- 12th Regiment, Infantry "Record of service of Michigan volunteers in the civil war, 1861-1865, v.12. Michigan", Pub. by authority of the Senate and House of representatives of the Michigan Legislature under the direction of Brig. Gen. Geo. H. Brown, adjutant general. This source gives the history of the regiment and the roster.
Companies in this Regiment with the Counties 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.
See Rosters, as there were men from many different Counties in these Companies
- Beginning United States Civil War Research gives steps for finding information about a Civil War soldier. It covers the major records that should be used. Additional records are described in ‘Michigan in the Civil War’ and ‘United States Civil War, 1861 to 1865’ (see below).
- National Park Service, The Civil War Soldiers and Sailors System, is searchable by soldier's name and state. It contains basic facts about soldiers on both sides of the Civil War, a list of regiments, descriptions of significant battles, sources of the information, and suggestions for where to find additional information.
- Michigan in the Civil War describes many Confederate and Union sources, specifically for Michigan, and how to find them. These include compiled service records, pension records, rosters, cemetery records, Internet databases, published books, etc.
- United States Civil War, 1861 to 1865 describes and explains United States and Confederate States records, rather than state records, and how to find them. These include veterans’ censuses, compiled service records, pension records, rosters, cemetery records, Internet databases, published books, etc.
- Lewis, George W., and Duane Jacobs. "Diary of George W. Lewis, June 4, 1865-Dec. 31, 1865: 12th Michigan Infantry Regiment". (Fordyce, Arkansas: Duane Jacobs, 1985). Other Libraries
- Michigan Adjutant General and George H. Turner. Record of Service of Michigan Volunteers in the Civil War, 1861-1865 [Twelfth Infantry]. Lansing, Mich: Michigan Adjutant-General's Dept, 1905. Digital Copy. FHL Fiche 6084660 . Other Libraries.
- Michigan Shilo Soldiers Mounument Commission. "Michigan at Shiloh" (Lansing: Michigan Historical Commission, 1920). pages 7-9. Digital Copy. Other Libraries
- National Park Service, The Civil War Soldiers and Sailors System (accessed 4 November 2010)