Oria Province, the Society
Cassia lives in a house in Mapletree Borough (at least until the Officials tear down the maple trees and rename it Garden Borough) in the futuristic Oria Province of a Society that exists where the United States used to be. Based on various maps readers have tried to make, Cassia lives somewhere between current Arkansas and current Montana. Really though, it could be set anywhere with sufficient technology to control the life and love of its inhabitants, all while convincing them that life is awesome and everything is perfect.
They've managed to eradicate all diseases and figure out how to keep people living an excellent quality of life until their eightieth birthdays, when they all just happen to up and die peacefully (now if that's not suspicious, we don't know what is). And the way this has all been arranged is through optimizing genetic matches—so everyone gets assigned their optimal genetic match at age seventeen and then marries and begins to procreate at age twenty-one, when fertility is at its prime.
To keep up this jig, the Society depends on everyone thinking this is just the peachiest idea ever, and not getting any ideas about wanting things to be any different. So everything about the Society is ordered and controlled, from the portion of food allotted for a meal to how everyone spends their free time to the culture that they're exposed to. Yup—only one hundred each of poems, paintings, songs, etc. made the cut. Considering this, it's kind of a wonder that anyone wants to live to age eighty.
There is, however, rumored to be a world outside the society, in the wild, scary Outer Provinces. They probably do crazy things out there, like choose whom they date and listen to rock and roll. We only catch glimpses of what life is like out there through Cassia's conversations with Ky, but we imagine we'll learn more in the rest of the trilogy.