In line 3, the speaker lets us know we are in Paumanok, but don't try to find that on any map. "Paumanok" is the name Native Americans gave to what is now known as Long Island, New York. It is indeed, as it is so aptly titled, an island; in fact, it's the largest and longest island in the United States. Naturally, it's known for its beaches.
So, we've got an exact place. Then, in line 6, we get an exact time. The speaker lets us know that the poem is set in autumn—you know, season of falling, colorful leaves and pumpkins. It all sounds pretty idyllic if you ask us.
Now that we have the place and season, then, let's dig a little deeper. The speaker walks along the shore, admiring the tide as well as the land beyond it, which is made up of fields and rows in the earth. This lets us know that he's in a part of Long Island that has few roads and not much traffic. Considering when the poem was written, we can guess that there weren't exactly major highways in his landscape. Nope—his surroundings are natural and wild.
They're also expansive. You really can't get much more vast than the ocean, after all. Take together, then, the elements of this setting combine for a fitting place for a rambling, soul-searching walk. All in all, we'd say that's the ideal backdrop for considering the role that nature plays in our lives.