We could be anywhere in "Democracy," and that's kind of the point. It doesn't matter where we are or what time it is; what matters is that all people ought to be free, no matter the specifics. Ambiguous, non-specific words like "land," "bread," or "seed" tell us the speaker is aiming to reach a wide audience with people who dig the concept of democracy in its most ideal sense.
So, if the setting sounds a bit open for interpretation, we know why. Even better is that the speaker has such an everyman's voice, which makes our setting even more open for interpretation. And even if we take into account the historical background of the poem and poet, we still feel as if "Democracy" is intended to go far and beyond the confines of its own space. Although it's an American poem by an American poet, we understand that the speaker's ideas are about people, not place.
So go ahead and fill in those blanks for yourself, because that's what the speaker was driving at all along. This is a poem about a what (freedom), not a where.