81st Regiment, Ohio Infantry
The 81st Regiment, Ohio Infantry mustered in September, 1861. Organized in Ohio at large, under authority granted by General Fremont, as Morton's Independent Rifle Regiment. They were mustered out July 13, 1865 at Louisville, Kentucky. 
For more information on the history of this unit, see:
- The Civil War Archive section, 81st Regiment Infantry, (accessed 31 August 2012).
- Larry Stevens' Ohio in the Civil War, 81st Ohio Infantry
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.
Company A - many men from Lima, Allen County
Company B - many men from Lima, Allen County
Company C - many men from Greenfield, Highland County
Company E - many men from Lima, Allen County
Company F - many men from Buena Vista, Adams County
The above information about the counties is from History of the Eighty-First Regiment, Ohio Infantry Volunteers, during the War of the Rebellion, by W. H. Chamberlin, (Cincinnati: Gazaette Steam Printing, 1865), p. 11-12, 172-197. Internet Archive.
- 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
- Chamberlin, William Henry, History of the Eighty-First Regiment Ohio Infantry Volunteers, (Cincinnati: Gazette Steam Printing House, 1865), 198 pages. Internet Archives. Google Book and (Washington [District of Columbia] : Filmed by the Library of Congress Photoduplication Service, 1987) FHL Film 1550216
- National Park Service, The Civil War Soldiers and Sailors System, (accessed 6 December 2010).