10th Regiment, Missouri Cavalry (Union)
This regiment was organized at Jefferson Barracks, Mo., October, 1862, from 28th Missouri Infantry. Bowen's Battalion asigned as Companies "A," "B," "C" and "D," and six Companies organized for 9th Missouri Cavalry assigned December 17, 1862, as Companies "E," "F," "G" and "H." Attached to District of St. Louis, Mo., to January, 1863. District of Memphis, Tenn., 16th Army Corps, Dept. of Tennessee, to March, 1863. Cavalry Brigade, District of Corinth, 16th Army Corps, to June, 1863. 3rd Brigade, 1st Cavalry Division, 16th Army Corps, to August, 1863. Cavalry Brigade, 15th Army Corps, to December, 1863. Winslow's Cavalry Brigade, 17th Army Corps, and District of Vicksburg to April, 1864. 2nd Brigade, 1st Cavalry Division, 16th Army Corps, to June, 1864. 2nd Brigade, Cavalry Division, Sturgis' Expedition, June, 1864. 2nd Brigade, 1st Cavalry Division, District of West Tennessee, to November, 1864. 1st Brigade, 4th Division, Cavalry Corps, Military Division Mississippi, to December, 1864. 2nd Brigade, Cavalry Division, District of West Tennessee, to February, 1865. 1st Brigade, 4th Division, Cavalry Corps, Military Division Mississippi, to May, 1865. 2nd Brigade, 4th Division, Cavalry Corps, Military Division Mississippi, to June, 1865. 
For more information on the history of this unit, see:
- The Civil War Archive section, 10th Regiment Cavalry, (accessed 21 July 2012).
Another source says the 10th Regiment of the Missouri Cavalry (Union) enrolled between 23 July 1861 and 22 October 1862. They were Mustered between 23 July 1861 and 17 December 1862. They were discharged between 11 July 1864 and 24 December 1865. They were led by Colonel Florence W. Cornyn.
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.
- Beginning United States Civil War Research gives steps for finding information about a Civil War soldier or sailor. It covers the major records that should be used. Additional records are described in 'Missouri 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.
- Missouri in the Civil War describes many Confederate and Union sources, specifically for Missouri, 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.
- National Park Service, The Civil War Soldiers and Sailors System, (accessed 5 Oct 2011 ).
- Kenneth E. Weant, Civil War Records Union Troops Missouri Volunteer Calvary, Volume 4 (Arlington, Texas : K.E. Weant, c2007), pages 63-83. FHL book #977.8 M2wkc v.4