Fort Marshall was considered one of Baltimore's more important defenses during the war. Its strong earthwork fortifications were positioned near to the center of the city. There it protected the eastern flank of the city, along with nearby Fort Worthington, from the threat of Confederate raid or invasion. Fort Marshall also shielded the Union military hospital at nearby Patterson Park, half a mile to the west. In addition, as the riots of April 1861 had proven, Baltimore itself was hardly a bastion of Union sympathizers, and so the fortifications served the dual role of enforcing the compliance of hostile Baltimoreans within, while protecting the city from Confederate attack from without. To this end, units from the Fort conducted regular patrols and drills in the city proper, for the purpose of, as one contemporary Union account put it, "reminding the city rebels that their masters were not far away." Celebrations of the Fourth of July at the forts of Baltimore involved large artillery salutes, both to commemorate the day as well as to serve as a "gentle reminder to the Secesh [secessionists] of that city that Fort Marshall was prepared for any emergency." Patrols from the fort also guarded lines and bridges along the Baltimore and Philadelphia Railroad after several bridges had been burned by saboteurs. Detachments from the fort were sent to various towns in Maryland's Eastern Shore in order to defend the polls during the 1864 United States elections, when pro-Union voters were facing voter intimidation. Troops were also sent on raids of nearby warehouses suspected of dealing in contraband or goods intended for smuggling to the South. One such incident uncovered a stock of gunpowder, bowie knives and short rifled muskets, worth at least $4000 () in a stash below Canton.