Answer:
This patch of land stands alone
It is in every mountain, it's not in any hill, it's not in all the world, and yet it's in the mill.
What has feet on the inside but not on the outside?
What kind of cup doesn't hold water?
When it's dirty this should never be aired in public.
I cover what's real; hide what is true, but sometimes bring out the courage in you. What am I?