The speaker arrives at Avebury, a place the title points to, and steps in among its standing stones. The opening image is odd and a little humble: "I go on one foot." It could mean hopping, limping, or simply moving carefully, as if the visitor is off balance in front of something much older than he is.
From there the poem is a string of short comparisons. The stones are like old people, "hard as tradition," "thick as wonder." They are tall, huge, and seem to grow out of the ground rather than having been placed there. The last image is the strangest and the most tender: stones "at the poor house, having their aches." Here the stones become elderly, worn down, and somewhat neglected.
The mood is reverent but gentle, even playful. The speaker doesn't treat the stones as a grand monument. He treats them as a crowd of ancient neighbours, awe-inspiring and also frail.