Country Star Billy Currington -- The HANDSOMEST Mug Shot Ever

He may be an alleged threatener of old people ... but DAMN Billy Currington takes good mug shot.

The criminally rugged country star new face of masculinity was arrested and booked in Georgia today after a grand jury indictment ... which TMZ previously reported.

In a nutshell, cops say Currington was upset at a 70-year-old tour captain for steering his riverboat too close to the Grammy nominee's dock ... so he allegedly jumped in his own boat and chased the old guy down ... to scream at him and threaten his life.

A grand jury indicted the "Pretty Good at Drinkin' Beer" singer on charges of making terroristic threats and abuse of an elder person.

Currington's bond was set at $27,000 ... cops tell us he's still in custody.