A ranger is typically someone in a law enforcement or military/paramilitary role specializing in patrolling a given territory, called "ranging" or "scouting". The term most often refers to: Park ranger or forest ranger, a person charged with protecting and preserving protected parklands and forests. National Park Service ranger, an employee of the National Park Service. U.S. Forest Service ranger, an employee of the United States Forest Service. Ranger of Windsor Great Park, a ceremonial office of the United Kingdom.
https://en.wikipedia.org/wiki/Ranger