The 48th New York was a Union infantry regiment that served in the Department of the South when it attempted to capture Charleston, South Carolina, during the summer of 1863. Recognized for its political, strategic, and maritime value, Charleston was targeted by the North early in the war. The Union Army's Department of the South and the Navy's South Atlantic Blockading Squadron were tasked with its capture. Despite their respective attempts to seize the city in mid-1862 and early 1863, Charleston remained firmly in Confederate hands. In June of 1863, Brigadier General Quincy Gillmore was assigned command of the Department of the South. The new commander believed that in order to capture Charleston, he first had to seize Confederate-held Fort Wagner on the northern end of Morris Island. He claimed that he and his men could take Wagner in less than a week. It would ultimately take them two deadly months. This thesis details the history of the 48th New York, and its contributions and exploits during this campaign. It also analyzes the profound effect this campaign had upon the spirit and character of the regiment for the remainder of the war.