William H. Wilson
Illinois Civil War Muster and Descriptive Rolls Database (Illinois State Archives):
       Wilson, William H. - Pvt - Co B - 20 IL US INF
        Residence, Joliet, Will Co, IL; Join, 13Jun1861-Joliet; Age, 18; Born, Butterfield, Somerset Co, ME
       Height 5' 10-1/2"; Hair, flax; eyes, blue; Complexion, light; Single; Cook
       Deserted at Jackson Tenn 12Aug1862
American Civil War Soldiers (ancestry.com)
      
Civil War Soldiers & Sailors System Search Detail (National Park Service):
        
National Graves Registration Database (Sons of Union Veterans of the Civil War):
      
Will County Illinois USGenWeb Necrologist Reports (© 2002 The ILGenWeb Project All Rights Reserved):

Headstone Reading,

Published Obituaries:

Additional Biographical/Historical Material:
          Regimental and Unit Histories - Illinois Adjuitant General's Report
                                                  20th Illinois Infantry
          May 14, 1861 - organized and went into camp at Joliet, Illinois
        June 13, 1861 - mustered into the service of the Unite States at Joliet, Illinois, for a term of three years.
          October 20, 1861 - activiely engaged in battle of Fredericktown
          April 6-7, 1862 - engaged in battle of Shiloh
          June 8, 1862 - marched into Jackson, Tenn.