The story does make use of symbols, beginning with the setting, which is on the railroad bridge. In this case, the bridge specifically is a symbol. Some commentators believe that author Ambrose Bierce, who fought with the Union, was prompted to write "An Occurrence at Owl Creek Bridge" because of the many incidents in which Southern sympathizers tried to blow up bridges or roads to make it impossible for the North to get much-needed supplies.
That may be so, but nevertheless, the use of the bridge as a setting serves as a symbol. What does a bridge do? It spans and connects two sides or two places. In the story, the bridge spans life and death for Peyton Farquhar and symbolizes the few moments of his hanging, during which he is in limbo between the two states.
The railway tracks also serve as a symbol of Peyton's life and existence, which are fading away. Specifically, the author writes that the "railroad ran straight away into a forest for a hundred yards, then, curving, was lost to view," just as Peyton’s future begins to fade away and become "lost to view."
In addition, the stream below the bridge is another symbol. In literature, water often represents life, renewal, cleansing, or freedom. In the story, the stream represents both Peyton’s life and his freedom. The author says that the:
swirling water of the stream racing madly beneath his feet. A piece of dancing driftwood caught his attention and his eyes followed it down the current. How slowly it appeared to move! What a sluggish stream!
How is it possible that the stream is both "racing madly" and "sluggish" at once? The last few moments of Peyton’s life are racing away, while at the same time, as his mind plays tricks on him so that he believes that he can escape and survive, he prolongs those last few moments while he is in between life and death and thereby slows the stream down.
Ambrose Bierce also uses colors as symbols in the story. The word "white" appears three times. The first is to describe the color of Peyton's wife's hands. The second is "the wide white walk" (also note the use of alliteration to drive home the importance of this image) he sees after he escapes his hanging and travels to his home. In both of these instances, white represents purity and something that Peyton loves. However, as he is about to embrace his wife (in his mind), "a blinding white light blazes all about him" and thrusts him into "darkness and silence!" The contrast between the white of the walkway that will take Peyton to his beloved wife and the white light that eclipses his life shows how quickly his dream of escape and his life are extinguished.