William Guest (b. ca. 1836) was the son of Catherine Guest (b. ca. 1806) and the brother of John Guest. (b. ca. 1843), Ellen Guest, and Isaac Guest. At the time of the 1860 Census, Catherine and William resided in the same household in Chester County, Pennsylvania. William’s occupation is listed as “carpenter,” and neither he nor his mother owned any property. William Guest mustered into service as a private in Co. F. 124th Pennsylvania Infantry (a nine-month regiment) on August 11, 1862 and mustered out with his company on May 16, 1863. He then enlisted in Battery F, 2nd Pennsylvania Heavy Artillery in February 1864, was promoted to Artificer, and mustered out on January 29, 1866.