Adrien Broner was sitting in a jail cell early Sunday morning -- 'cause the guy got picked up by cops in one state ... for being wanted in another.
The boxer was arrested and booked around 1 AM, getting hauled into the Kenton County Jail in Kentucky ... where he posed for this mug shot. The charges he got rung up on upon entry ... fugitive from another state, from which a warrant was required.
No word on the circumstances of how cops stumbled upon Broner to begin with, but they did.