Riley's mind is very large and includes locations like:
- Headquarters: the central part of Riley's mind, where Anger, Disgust, Joy, Fear and Sadness live and control Riley, and where her memories are produced.
- Islands of Personality: five prominent constructions standing just on the edge of the Memory Dump. They represent defining aspects of Riley's personality, as determined by the core memories.
- Long Term Memory: enormous banks of memories forming one of the most omnipresent parts of the mind.
- Imagination Land: a place where everything Riley imagines is built.
- Dream Productions: where dreams are filmed.
- Subconscious: contains Riley's worst fears.
- Abstract Thought: a place where ideas (or anyone inside) are simplified to an abstract concept.
- Train of Thought: a train that connects Headquarters and the rest of the mind.
- Memory Dump: an abyss surrounding Headquarters, where faded memories end up and eventually disappear.
It is hinted that there are many more places within her mind in addition to those visited in the film, such as Inductive Reasoning, Déja Vu, Language Processing, Déja Vu, Critical Thinking, and Déja Vu.
When Riley is awake, the "sky" is lit up. When she is asleep, it goes dark, revealing the glow of the memories stored in Long Term. When Riley's personality breaks down as she runs away, the sky becomes dark like a gathering storm.
A large amount of individuals known as "mind workers" live and work Riley's Mind. These include:
- Figments of imagination
- Imagination Land construction workers
- Cloud people
- Dream Productions cast & crews
- Subconscious Guards
- Mind Worker Cops
- Unnamed second cop
- Jangles the Clown
- Train of Thought Conductor
- Fritz the repair worker
- One of her memories is the playground of Sunnyside Daycare from Toy Story 3, with the only difference being that the slide is not coiled, but straight.
- It would appear that Headquarters acts as the main source of illumination (the sun and moon) inside Riley's mind, as everything lit in Riley's mind tends to face headquarters. There is also a strong "sun like" glow emitting from HQ when looking directly at it.
- According to Sadness, the expanses of Riley's mind are endless and do not have a set ending point. Far off in the distance of her mind, as seen in a few shots, are larger structures sticking up like buildings. Upon further examination, many of them seem to still be shelves of Long Term Memory, only taller in height.