London is the primary setting for the novel, and the country village where the Maylies go on vacation serves primarily as a contrast to London (see the "Contrasting Regions" theme for more on that). The city is repeatedly described as a labyrinth or a maze – once you get into it, it’s hard to get back out. The city itself serves as a kind of prison. It’s filthy, foggy, and crime-ridden, and things aren’t always what they seem. For example, Oliver gets dragged "into a labyrinth of dark, narrow courts" (15.63), and Fagin "becomes involved" in "a maze of mean dirty streets which abound in that close and densely-populated quarter" (19.4).
The village in the country where Oliver is so happy with Rose and Mrs. Maylie (Book Two, Chapters Nine and Ten) is the total opposite. The narrator suggests that the country can actually "cure" some of the bad effects of the city: "Who can tell how scenes of peace and quietude sink into the minds of pain-worn dwellers in close and noisy places, and carry their own freshness deep into their jaded hearts?" (32.51). But even in the country, Oliver isn’t safe from Fagin’s criminal network. Even the pristine and tranquil country cottage can be invaded by bad visitors from the city, who disappear like ghosts without leaving footprints (2.11). Dickens might be suggesting that the city is more powerful – its evil representatives, after all, are able to penetrate into the country, while elements of country life seem only able to survive on the fringes of the city.