We have to do double duty when talking about the setting for this poem, because it takes place in two totally different locations. And bonus, each of these places has both a literal and a figurative meanings. Don't worry, we'll explain.
Where the Sidewalk Ends
First, of course, we've got the land where the sidewalk ends. We could go the boring route, and just think of a normal countryside, away from the suburbs and the city. But we could also blast off into a land of fantasy that exists only in our imaginations.
The speaker of the poem mentions that there are moon-birds flying in peppermint winds over soft white grass, against a perpetual sunset. From there, we are encouraged to imagine all the other lovelinesses living here: gently rolling hills, waterfalls that slide right down into a pool of bubble bath, trees laden with fruits that taste like mint chocolate chip ice cream… okay maybe Shmoop's getting ahead of ourselves, but we can't help thinking, hey, it could happen. Isn't that precisely the point?
The Other Place
But a place like this wouldn't be so delightful if it weren't contrasted with anything. So, after the poem describes the wonderful world out where the sidewalk ends, it tells us a little about the world we're escaping – our second setting. This world can be taken to literally mean any city with the black smoke of factories and exhaust, and the endless miles of pavement, bricks, and litter. Although if we're willing to take a bit of a leap, we might guess that the city we're talking about here could be Chicago, where Shel Silverstein is from. Chicago is big, industrial, and chock-full of sidewalks, so it would certainly fit the bill.
We can also think about it more figuratively and transplant the bleak city world into the realm of our own mind. Maybe it represents the dark parts of our brain, the places where all the joy and innocence has been worn away by the daily grind.
But, luckily, if we pay attention to some simple signs left for us by the child inside us all, we can get to the world where the sidewalk ends. We don't even have to leave the city or even our chair (yay!), because the world where the sidewalk ends is inside our heads.