“A Horseman in the Sky” is set in western Virginia during the American Civil War in the 1860s. In the Civil War, Southern Confederate states (including Virginia) sought to secede from the Northern Union states in order to continue the practice of slavery. In the story, Druse chooses to fight for the Union while his father fights for the Confederacy, an example of the ways that the Civil War split some families down the middle.
In Part 1 of the story, Bierce spends several paragraphs describing the specific geography of Virginia, where Druse and his fellow Union soldiers are planning their attack, as seen in the following passage:
The configuration of the valley, indeed, was such that from this point of observation it seemed entirely shut in, and one could but have wondered how the road which found a way out of it had found a way into it, and whence came and whither went the waters of the stream that parted the meadow more than a thousand feet below.
No country is so wild and difficult but men will make it a theatre of war.
Here, the narrator helps readers picture the setting of the story—by describing the road, the stream, and the meadow—and also helps them understand that this is “wild and difficult” country. Because the valley is “shut in,” Druse and the Union soldiers could easily be trapped if the Confederate soldiers found them. At the same time, this particular setting facilitates their plans to sneak up on and ambush the Confederates.
Bierce sets the story in this precarious environment in order to make the stakes of Druse's decision to kill his father clear—either he kills his father or puts his fellow Union soldiers at risk (as his father could alert the other Confederate soldiers of their whereabouts). The narrator’s statement at the end of the passage that men will turn any geography into “a theatre of war” is one of the few moments when Bierce’s anti-war stance comes through clearly in the story.
