Prentisstown, the Countryside of the New World, Farbranch
We see a couple different settings in The Knife of Never Letting Go, so we're going to give you a tour of the highlights: the bad, the good, and the better.
Imagine the worst day you've ever had. Now imagine that being every day. Okay, now you can imagine what it's like to live in Prentisstown.
Prentisstown is more about how you feel when you're there than what it physically looks like. And it is one Noisy, angry, womanless place. Todd hates "every minute of every day in my stupid, stinking life in this stupid, stinking town" (2.21). The fact that everyone is so unhappy is made way worse by Noise—you don't just hear your own unhappiness, but the unhappy noise of everyone else. It's enough to really bum a person out.
Basically, Prentisstown is the armpit of the New World. So even though Todd leaves it at the beginning, since the town is where he's been raised, it's responsible for all the anger he carries. The Prentisstown vibe taints everything it touches.
New World Swamp / Countryside
Most of Todd's journeys take him through the countryside of the New World. It's a nice break from all those settlements with their weird laws and quirks, and since so much of the book deals with society (and all the things that can go wrong with it), it's important that there's this neutral ground.
Todd finds the countryside "all just life, going over itself, returning and cycling and eating itself to grow" (1.60). In other words, it's self sufficient and happy, without Noise and people ruining everything. He says there is "no sign of any kind of settlement or people except for the dusty road itself. Which is good in one way but weird in another" (20.52). To Todd, after all, the world as he knows it is meant for people to crowd and control. The countryside, then, offers him a new way of thinking about the world and how to live in it.
Farbranch is probably the golden child of the New World (well, until Mayor Prentiss flattens it to the ground). Todd, who's used to towns being like Prentisstown, says that "it feels like I've wandered right off New World into some whole other place altogether" (17.84) when he gets here. People aren't angry and they seem to get along pretty well—even with Noise. Compared to the Noise he's used to, it's "so heedless and safe-sounding to me that it feels like taking a bath in comparison to the black Noise I'm used to" (17.89). Todd's mind's a little bit blow, and that's only a good thing.