The papers of Union soldier Samuel J. Gibson (1833-1878) consist of a diary kept by Gibson in 1864 while serving with Company B, 103rd Pennsylvania Infantry Regiment, and a letter to his wife while held as a prisoner at Camp Sumter in Georgia, the Confederate prisoner of war camp commonly known as Andersonville Prison. The diary documents the capture of the Federal garrison at Plymouth, North Carolina, in April 1864, and Gibson’s experiences as a prisoner of war at Andersonville, Georgia, and Florence, South Carolina. Gibson records war news and rumors received by the prisoners, the state of his physical and emotional health, the deaths of fellow prisoners, and the importance of his diary in maintaining a sense of time.