Low Lords by T. R. Pearson

Eighteen-year-old Hoyt MacKenna — friends and family call him Mack — was born a Low Lord in Cumberland, Tennessee. That makes him part of a secret society founded by statesman and inveterate caver Thomas Jefferson. Low Lords are cavern minders, each group a family unit. The clans rotate to new sites every eight years or so and, as much as possible, live apart from the general population so as to devote themselves to their sole duty of keeping what's under down.

Low Lords is a family-friendly, quasi-historical freak show of a fantasy, a coming-of-age story with headlamps and monsters

" An American original. Pearson has invented his own world." Los Angeles Times