What is the name of the location where forgotten memories are discarded?

The location where forgotten memories are discarded is called the Memory Dump.

In Inside Out, memories are stored as colored orbs in Riley’s long-term memory. Mind Workers called Forgetters sort through these memories and remove ones that are no longer considered important. The discarded memories fall into the Memory Dump, a vast, dark area where they gradually fade away forever.

Joy, Sadness, and Bing Bong enter the Memory Dump while trying to return to Headquarters. Bing Bong’s rocket wagon cannot escape because he and Joy are too heavy together, leading to his sacrifice so Joy can get out. The scene gives the Memory Dump an emotional purpose beyond being a storage site.

The Memory Dump is often confused with Long Term Memory, the larger region where memories are stored, or Abstract Thought, a separate area that transforms characters into increasingly simplified shapes.