Maria Guild sold her Detroit property in February of 1861 (she was living in Detroit when the 1850 census was taken); she was already living in Flint for the 1860 census.
Wayne Co., Michigan, Land Records
11 February 1861
Maria Guild, of Flint, Genesee Co., Michigan
Daniel Day of Detroit
E 1/2 of Lot 14 in Brown's Subdivision of Park lots 84, 85, & 86 on Adams Avenue in Detroit
Witnesses: Dewitt Parker & L. Lathrop
Maria obtained a pension based upon the Civil War military service of her son, Simeon Guild, who was a Captain in the 8th Michigan Infantry. The pension application stated that "Simeon was constantly in the habit of supporting his mother prior to him going to the University of Michigan." It was also mentioned that Simeon taught school...
Simeon was killed in action on June 16, 1862, at James Island, South Carolina, "falling a victim in the affair at Fort Wagner...". The battles on June 16, 1862, include Secessionville/Ft. Lamar/James Island (not Ft. Wagner). A map of the battle, including the Michigan 8th Infantry's position, can be found here.
Source: History of Genesee County, Michigan, by Franklin Ellis