Riley Andersen, Age 11
You read that right. An eleven-year-old girl from California by way of Minnesota is the primary setting for Inside Out. We see what happens to Riley in the physical world, too, as she moves to San Francisco, starts a new school, and (briefly) runs away, but the bulk of Inside Out's action goes down in between Riley's ears.
How About a Side of Symbolism with Your Metaphor?
The fact that the film's setting is a pre-teen's mind means that the world our main characters inhabit is a huge hodgepodge of vivid metaphors, where the various elements that make up Riley's consciousness take recognizable forms. Riley's individual personality traits are represented by islands, for example. Her dreams are produced at a busy, Hollywood-style film and television studio, complete with cameras, sets, and actors.
While we're at it, those main characters we just mentioned are also metaphorical representations of abstract concepts. Joy, Sadness, Anger, Disgust, Fear: these aren't tangible things—you can't run to the corner store and buy a bag of disgust (not unless you count week-old breakfast burritos).
The Only Rule is That There Are No Rules
Because the setting's a lively mass of metaphors, there's no limit on how it should look, or how characters can interact with it. The fact that Inside Out is animated only doubles down on this "the only rule is that there are no rules" approach to location.
Riley's train of thought is an actual train? Sure! Why not? Memories that are no longer useful or relevant, like piano lessons or obscure presidents, get sucked up and disposed of with a vacuum the same way you might hoover up the dust bunnies beneath your bed. Those memories themselves are little color-coded symbols of recollection and sentiment that barrel through a twisting tunnel system like an emotional rollercoaster.
As peculiar as it is, Riley's mind is strangely familiar, even though we've never been there before. We've all had carpets turn into lava, imaginary friends (and boyfriends or girlfriends who conveniently live in Canada), and high-definition dreams where we're pants-less at school.
Setting aside murkier corners like the Memory Dump and Riley's Subconscious, Riley's mind resembles a board game come to theoretical life, or perhaps a theme park. It's bright and colorful, and everything is neatly divided into concept-specific worlds, lands, and islands.
The only thing missing in Rileyland is an actual Stream of Consciousness. Joy and Sadness could have paddled their way back to HQ in a jif.