The Thomas Hall diary is a pocket-sized volume containing entries for August 28, 1862, to August 20, 1863. The diary documents Hall's Civil War participation in the 110th New York Infantry, from the time of his enlistment until a few days before his death from heatstroke and disease on August 25, 1863. In a series of brief entries, Hall described his regiment's experiences in Virginia; Maryland; Ship Island, Mississippi; New Orleans, Louisiana; and Port Hudson, Louisiana.
The opening entries of the diary are quite terse, generally providing only one to two lines of basic information. They primarily concern such topics as Hall's location, the letters he received and wrote, his church attendance, and his military activities. However, beginning in November 1862, Hall wrote with greater detail about his surroundings and actions. On November 5, 1862, he described the regiment's departure by steamship from Baltimore, noting that the bay was "dotted with sail vessels and steamers." While onboard the ship, he noted mechanical problems, extreme weather, his ship-related duties, health concerns, his surroundings, and food. During mid-November, while the regiment sailed south for New Orleans, he mentioned regular drilling using "the manual of arms" (November 10, 1862), and a brief stint in the hospital (November 13, 1862). On November 20, 1862, he wrote that he had visited the Virginia plantation of Confederate General John B. Magruder.
Soon after his arrival in the Deep South, Hall noted his extreme dislike of Ship Island, Mississippi, which he hoped never to see again (December 29, 1862), and referred to his time with military and the inexperience of the officers in his regiment. In the same entry, he lamented that he saw "No better prospect of peace then [sic] one year ago" (December 31, 1862). He also discussed the capture of a Confederate plantation near Carrollton, Louisiana, including the confiscation of its ducks and chickens (January 13, 1863) and the arrest of a soldier, Thomas Lake, for intoxication, commenting, "The devil to pay generaly [sic]." By mid-March, operations against Port Hudson, Louisiana, had begun, and Hall's entries mainly focused on these developments. He noted that each man now carried six days' rations (March 11, 1863), described the bombardment of Port Hudson as "fire & explosion on river" (March 15, 1863), and gave an account of a march through knee-deep mud (March 18, 1863). On April 12 and 13, 1863, Hall briefly commented on the Battle of Fort Bisland, noting that fighting had ended at 6 p.m. and the Confederate band had played "Dixie." Subsequently, he mentioned the capture of Confederate prisoners near Franklin, Louisiana, (April 15 and 16, 1863) and the poor condition of the men in his regiment due to a lack of regular rations and the absence of the quartermaster (April 25, 1863). On May 26, 1863, he discussed a skirmish near Port Hudson, stating that "marshy ground" had caused the Union artillery to fail. Other entries note the surrender of Port Hudson (July 8, 1863), the suicide of a man in the regiment (July 8, 1863), and a Zouave's failed attempt to escape from Port Hudson (July 9, 1863).
In his diary, Hall also wrote about several experiences with African Americans. On November 20, 1862, he recounted tricking an African American who sold him "ginger cakes." According to Hall, the man "could not count" and Hall exploited him by taking more cakes than he had purchased. Near New Orleans, he described buying bread from "an old negress who had a Mexican man…. Her man was lame and she supported Both" (December 19, 1862). On another occasion, he noted that several friends had gone to the "negro quarters" in Carrollton, Louisiana, and danced nearly all night (January 10, 1863). On March 4, 1863, he mentioned that the "contrabands expect to march tomorrow," but he gave no further details.