William Henry Johnson was a Private in Company B of the 1st New York Cavalry Regiment during the Ameircan Civil War. On December 4, 1861, Johnson deserted the Union Army and attempted to make his way south to the Confederate front-lines. While making his way to the Confederate lines he encountered a Union reconnaissance unit returning from patrol, whom he mistook as Confederates. After identifying himself as a Union deserter and offering to provide the location of Union pickets, he was placed under arrest and taken to the Provost Marshal. Johnson was subsequently court-martialed and sentenced to death. Johnson’s execution took place on December 13, 1861, and marked the first time that a deserter was executed by the Union Army.

External Source:

"The 13 December 1861 Execution of Pvt. William Henry Johnson at Fairfax Seminary" (Dec. 12, 2011), Civil War Washington, D.C. blog, http://civilwarwashingtondc1861-1865.blogspot.com/2011/12/13-december-1861-execution-of-pvt.html, accessed May 2023.