Xanadu, during the reign of Mongol emperor Kubla Khan
Coleridge has a lot to say about the setting of this poem. He devotes many lines to describing the landscape, the caverns, and the sea. That works for the first half of the poem, but then that Abyssinian maid shows up, and then there are the flashing eyes, and the milk of a paradise. All this new stuff makes it hard to believe we're still in the same place as the river and the palace. Maybe we need a setting that can encompass this whole experience.
So here's what we think: This poem could take place in a kid's bedroom. Remember that age when you were really excited about faraway places and legends and monsters? Imagine Coleridge as your cool uncle who told you amazing, spooky bedtime stories. "Kubla Khan" is sort of about a person and a place, but it's really more about how you can create those things with words alone. That's the heart of the bedtime story. You didn't need pictures or movies or a plane or any other props. Coleridge needed sleep and sickness and drugs in order to have this vision. But the amazing thing about this poem is that he can recreate this experience without any of those things. He just needs the sound and the texture of words. So, imagine yourself tucked in on a rainy night in winter, just a candle lighting the room, listening to Coleridge build castles with his words.