A Johnson County woman is dead after a one-vehicle accident early yesterday morning. According to a release from the Illinois State Police, the woman, whose name has not yet been released but was listed as a Grantsburg resident, was driving south on Mount Zion Road just north of Illinois 146 when the vehicle left the roadway and overturned. The woman was pronounced dead at the scene and police say that she was not wearing a seat belt. The crash remains under investigation.