Where It All Goes Down
The Fictional Country of Costaguana
Costaguana is a fictional South American country loosely based on Colombia. Most of the action takes place in Sulaco, a port town (which is also totally made up).
Understanding the geography of Sulaco and the surrounding areas is pretty important, which is probably why Conrad starts the book with an entire chapter devoted to setting—no characters, no action. In addition to giving us a ghost story that serves as a metaphor for some of the characters' behavior (see "Symbols"), this chapter provides a crystal clear picture of the topography of Sulaco's surroundings.
Check out the first paragraph:
In the time of Spanish rule, and for many years afterwards, the town of Sulaco—the luxuriant beauty of the orange gardens bears witness to its antiquity—had never been commercially anything more important than a coasting port with a fairly large local trade in ox-hides and indigo. The clumsy deep-sea galleons of the conquerors that, needing a brisk gale to move at all, would lie becalmed, where your modern ship built on clipper lines forges ahead by the mere flapping of her sails, had been barred out of Sulaco by the prevailing calms of its vast gulf. (I.1.1)
This first chunk of text gives us a lot of really important information. First: Costaguana has been conquered by Europeans for some time. We end up learning that European conquest is kind of a big topic for the novel, and Conrad signals as much by putting a reference to it in the very first sentence.
Also, we learn that Sulaco hadn't exactly been a commercial hub because of its geography. That kind of explains why Gould was so keen to get an industry going there.
Finally, the narrator mentions how calm the wind in the gulf is, making it difficult for boats to move around the harbor. That's not just a throwaway detail, y'all—that aspect of the wind becomes important later, when Nostromo and Martin are trying to escape Sulaco, and it's slow going because they get enough wind in their sails.
We think you get our point. If you don't understand the geography of the place, it's going to be hard to follow all the political maneuverings and challenges the characters face. So, Conrad is wise to give us a chapter giving us the lay of the land; it's useful and signals how important geography is going to be for the rest of the book. You know what they say—it's all about location, location, location.