Although we don't know the man's name nor exactly what crime he has committed during Part I of the short story, we do know that a man is about to be hanged on a railroad bridge in northern Alabama--presumably over the Owl Creek of the title. The man who has a noose about his neck is dressed in civilian clothes while the rest of the men present are in Federal army uniforms. They have prepared a makeshift gallows: The noose is attached to a beam above, while the condemned man is standing on a board that hangs only part way across the tracks. A Union sergeant stands on the other secured end. When the sergeant steps off the end of the plank, the condemned man will fall between the railroad ties.
The condemned man is apparently a Southern sympathizer and a plantation owner. As he awaits his death, he becomes fixated on the passing of time: how "sluggish" the current is below, and how the ticks of his watch seem as loud as "the stroke of a blacksmith's hammer." The intervals between each tick slows to "maddening" intervals. He thinks of his wife and children back home as the Federal officer gives the signal for the sergeant to step aside.