Most golfers and golf fans understand the concept of out of bounds on a golf course. A golf ball goes out of bounds when the ball is hit outside the property line of the golf club or golf course. However, at some golf clubs and for some specific golf tournaments, there is this concept of internal out of bounds or in-course out of bounds. It is a jarring idea to a lot of players, but it's typically done for a reason.
What is internal out of bounds on a golf course?
In-course out of bounds is an area of the golf course or club that is considered out of bounds despite being an apparent part of the course. The internal out of bounds may apply to a specific part of the course at all times, or it can sometimes be applied just to a specific area of the property when a player is competing on a specific hole or set of holes.
Historically, internal out of bounds represented a plot of land or a piece of property the club actually didn't own. That was the case at Royal Portrush in the 2019 Open Championship. Though the club now owns the land off their first fairway, the club continues to play those portions of the property as internal OB.
Many golf courses consider their practice facilities internal out of bounds if they adjoin the golf course in any way. That's standard practice, so as to keep golfers from wandering onto the driving range just to hit a shot and risk injury.
However, some golf courses declare specific parts of the course as internal out of bounds when they don't want competitors or everyday players hitting their golf ball to other parts of the course to create better angles for shots. Sometimes this is done to prevent players from cutting off too much of a hole. Sometimes this is done simply for player safety, so as to prevent any potential injuries to players who might not be expecting golf balls to fly in their direction. Typically, it's both. This happens on the PGA Tour on the 18th hole at the Sony Open in Hawaii at Waialae Country Club.
What is the penalty for hitting into internal out of bounds?
The penalty for hitting into internal out of bounds on the golf course is the same as hitting it out of bounds under normal circumstances. It is a stroke-and-distance penalty, meaning a player must add one to their score for that hole and then hit the ball again from the exact same spot (or on the teeing ground if done on the tee shot) as their previous shot.