On a par 3 at my local course next to the green there is a small retaining wall built around a tree that is made of stones. The stones are clearly arranged to create a wall about two feet high. If I hit a ball so it is laying against the wall, can I take relief under the immovable obstruction rule?

If the answer is no because stones are natural and not artificial, could I take relief if there was a metal stake running through the wall and my ball was was laying against the metal stake?

Thanks.

Although the stones are natural, the wall is manmade. It is very likely an immovable obstruction. The only reason it wouldn't be was if a local rule has declared the wall to be "an integral part of the course."

What would be an example of "an integral part of the course'?

An integral part of the course is basically an artificial construction that is deemed by the Committee to be an integral part of the course instead. So, you can play it as it lies or declare it unplayable. Examples of things that might be deemed an integral part of the course that I have seen: railroad ties defining the sides of bunkers, maintenance roads, retaining wall building up the side of a tee or green, and wrappings around a tree. Hope that helps.

For the record, one other possibility it wouldn't be an immovable obstruction is if it defined out of bounds, but it doesn't sound like that from the O.P.'s description.

It did not define out of bounds. Also, for the sake of argument, assume that there is no local rule declaring the area "an integral part of the course."

Then as long as the wall interferes with your stance or swing (not your intended ball flight), you may take a free drop within one club length of the nearest point of relief no closer to the hole.