28th Regiment, Tennessee Cavalry (Hay's)
"No record of authorization for this regiment was found except in parole records in 1865, most of them dated May 16, 1865, at Chattanooga, Tennessee. It was probably formed in 1865 by the addition of other companies to a battalion of Cavalry or Scouts commanded in December, 1864 by Captain Jourdan Hays. On December 11, 1864, Lieutenant General John B. Hood, with headquarters on the Franklin Pike, six miles from Nashville, advised Colonel Benjamin I. Hill, commanding at Shelbyville: "Captain Jourdan Hays, cornmanding a battalion of Cavalry, has been ordered to report to you with his command, without delay. His battalion will constitute a portion of your command." On the same date, instructions were issued to Captain Jourdan Hays, near Winchester, to report to Colonel Hill. On December 14, inquiry was made as to whether Captain Hays had reported as ordered. This is the only record found on Captain Hays' Battalion." 
"Units of the Confederate States Army" by Joseph H. Crute, Jr. contains no history for this unit. 
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 'Tennessee 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.
- Tennessee in the Civil War describes many Confederate and Union sources, specifically for Tennessee, 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.
- Tennesseans in the Civil War, 28th Tennessee Cavalry Regiment, (accessed 29 Dec 2011). A brief history, officers and captains are listed.