Beacon Heights is a satellite around Seattle, Washington, where the girls live and the book series is set in.
According to the book, "In many ways, Beadon Heights looks like any affluent suburb: Porch swings creak gently in the evening breeze, the lawns are green and well kept, and all the neighbors know one another. But this satellite of Seattle is anything but average. In Beacon, it’s not enough to be good; you have to be the best." They reportedly have some of the best students in the country, signaling a good education program.