From where the house and barn were in Yellow Sky, one just moves along to the north to get to the waterhole used in the movie. The distance away is exactly like what you see in the movie.
As you can see, this really is not a waterhole at all, but it is what they used. 
You can see the rock Anne Baxter is heading to.
In this picture you should be able to pick it out. What I am calling the "trail" to the waterhole is on the right. 
This is the scene where one of the outlaws grabs Anne, but then the younger outlaw tries to stop him.
This is close. The rocks to the left are the guides to this.
Gregory Peck comes and gives the outlaw a nice kick. Notice Richard Widmark standing behind the tree. BTW, all the trees you see appear to be just set pieces. Just like water was added to create this waterhole for the movie.
Almost like this.
This should give you an idea how the waterhole area was used in the movie.
YS: The Waterhole (Youtube Version)
