Thomas Hardy's poem "Paying Calls" is about a man who has come to a place in his life which makes him reminisce about his past. He begins to make calls upon those he has not contacted in a very long time.
Hardy states that he strayed a mile from "where the bustle ends." One could imagine that Hardy has found himself in a cemetery. This can be justified because the bustle of life ends at the grave.
One could go on to support this through the lines in the third stanza:
It was the time of midsummer
When they had used to roam;
But now, though tempting was the air,
I found them all at home.
Here, one could justify that "home" was their final resting place.
The final key to support the fact that Hardy is standing next to "mound and stone and tree" (graves). He has come to the final resting place to speak to friends long gone who fail to speak back to him.
The entire poem speaks to the theme of importance of friendships. While Hardy's friends are dead, the fact remains that he still feels a connection to them, especially to those who are his "oldest friends of all." While in body his friends may be gone, but their spirit and the memory of their friendships will never leave him.