chapotraphouse

Its actually most of the US: https://en.m.wikipedia.org/wiki/Child_marriage_in_the_United_States

Although that's with all the exceptions on the book. It might be easier to get the exceptions in the bible belt.

Also notable: states with zero minimum age using all exceptions CA, OK, NM, MS.

Edit: in 2017 there were 25 states with no minimum age. All 13 states with 18 as the final minimum were applied after 2018. The triggering event seems to be HRW pointing out Afghanistan had better child marriage laws than the US. So this is something that the US is just now coming to terms with.

Outside the Bible belt too; the fundamentalist Mormons in Utah, Arizona, Nevada, Colorado, and New Mexico also have child brides, but I think they're more reprehensible since they also expel their teenage boys by abandoning them in Phoenix, Salt Lake City, Denver, Albuquerque, and Las Vegas to a life of destitution due to being uneducated and sheltered their entire lives in cult like conditions.

They also have complete control of the towns they inhabit including the police and judiciary to shield them from state efforts to stop them; with Colorado City being the most egregious example imo.