Out of bounds definition
“Out of bounds” refers generally to all areas outside the boundary edge of the course. Under Rules of Golf play is not allowed there. This term is often abbreviated as “O.B.”, “OB” or “O.O.B.”.
Most often all areas inside that edge are in bounds. However sometimes for safety reasons, a particular part of the course may be specified as “internal” out of bounds during the play of a particular hole. This can be done for example to prevent a player from cutting the dogleg by playing a ball to the fairway of another hole.
Boundary edge of the course
The boundary edge of the course extends both up above the ground and down below the ground. It is defined by stakes, boundary objects or lines. Boundary stakes or lines should be white.
When OB is defined by stakes or a fence, the boundary edge is defined by the line between the course-side points of these objects at ground level. Boundary objects are out of bounds. They cannot be removed without clear permission stated in the Local Rules.
When OB is defined by a painted line on the ground, the boundary edge is the course-side edge of the line, and the line itself is out of bounds. It that case, stakes may be used to show where the boundary edge is, but they have no other meaning.
When OB is defined by other objects such as a wall or road the boundary edge is clearly and specifically defined in the Local Rules and mentioned on the scorecard.
When a ball is out of bounds?
A ball is out of bounds only when “all of it is outside the boundary edge of the course“. A ball is in bounds when “any part of the ball lies on or touches the ground or anything else inside the boundary edge, or is above the boundary edge or any other part of the course“.
See the pictures below – the boundary edge of the course is marked by black dashed line.
update: March 2021