12th Regiment, Ohio Infantry
The 12th Regiment, Ohio Infantry mustered in June 28, 1861 at Camp Dennison, Ohio. They were mustered out July 11, 1864 at Columbus, Ohio. 
For more information on the history of 12th Ohio Infantry see the following:
- Larry Stevens' Ohio in the Civil War, 12th Ohio Infantry
- The Civil War Archive section, 12th Regiment Infantry, (accessed 29 August 2012).
- The Wikipedia article, 12th Ohio Infantry (accessed 12 October 2011)
- Ohio Civil War Central, 12th Regiment Ohio Volunteer Infantry (1861-1864), (accessed 26 October 2016)
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.
Many men from Clinton County.
- 12th Ohio Regiment Infantry (3 years), Civil War Index, which includes history, battles, and roster with name, rank, age, date entered service, period of service and remarks.
- 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 ‘Ohio 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.
- Ohio in the Civil War describes many Confederate and Union sources, specifically for Ohio, 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.
- Owens, Ira S. Greene County in the war : being a history of the Seventy-Fourth Regiment : with sketches of the Twelfth, Ninety-Fourth, One Hundred and Tenth, Forty-Fourth, One Hundred and Fifty-Fourth regiments and the Tenth Ohio Battery : embracing anecdotes, incidents and narratives of the camp, march and battlefield and the author's experience while in the army. (Bethesda, Maryland : University Publications of America, c1993), FHL fiche 6118222 -3 and (Washington [District of Columbia] : Filmed by the Library of Congress Photoduplication Service, 1988), FHL film 1486451
- Scott, William Forse.Philander P. Lane, colonel of volunteers in the Civil War, Eleventh Ohio Infantry. (Bethesda, Maryland : University Publications of America, c1993) FHL Fiche 6118153
- United States. Army. Ohio Infantry Regiment, 20th (1861-1865).History and proceedings of the 1st annual reunion, Twentieth Ohio Infantry. (Columbus, Ohio : Ohio Historical Society, 1988) FHL Film 1688765 Item 2
- Ward, James E. D. Twelfth Ohio Volunteer Infantry. (Ripley, OH: [s.n.], 1864). Libraries with book and (Columbus, Ohio : Ohio Historical Society, 1988), FHL film 1688762 Item 8 and (Bethesda, Maryland : University Publications of America, c1993), FHL fiche 6118154
- National Park Service, The Civil War Soldiers and Sailors System, (accessed 6 December 2010).
-  History of Clermont County, Ohio, (Philadelphia, Pa.: L.H. Everts, 1880), page 202, 205-6.
- E. M. P. Brister, Centennial history of the City of Newark and Licking County, Ohio (Defiance, Ohio: Hubbard Company for the Licking County Genealogical Society, 1982). p. 210
-  "History of Clermont and Brown Counties, Ohio: from the earliest historical times down to the present", by Byron Williams, (Tucson, Arizona: Filmed by W.C. Cox Co., 1974), page 426.
-  History of Highland County Ohio, page 141.
-  History of Clermont County, Ohio, (Philadelphia, Pa.: L.H. Everts, 1880), page 206.
- The History of Clinton County, Ohio (Chicago: W. H. Beers & Co, 1882) p. 454