Where It All Goes Down
21st Century United States
From Pennsylvania to Florida to Arizona, Gratuity sure does travel the country in this book. Yet, the book isn't so much about the distinct landmarks of these locations as it is about her world being turned upside down. The fact that everywhere from Happy Mouse Kingdom (Disney, anyone?) to the freeways are destroyed by the alien invasion is upsetting to Gratuity.
Perhaps one of the reasons the story's set right in her backyard (you know, if you can call a country someone's backyard) is because it gives us a chance to read about places we're familiar with. Everything changes when the aliens invade, and one way for us to really see that is through watching our own points of reference get destroyed.
As for being set in this day and age, instead of in the future or some other super different time period, this makes us think about what it would be like for Boov to come knocking right now. You better get the door.