The Memory Dump is a location in Inside Out inside Riley's mind. It constitutes the bottom of the mind, making an abyss under Headquarters and the Islands of Personality. Faded memories as well as discarded material from Imagination Land are thrown in it, where they pile up and eventually disappear, forgotten. It is said that nothing ever comes back from the dump.
During the course of the film, many things fall into the Memory Dump as Riley's life plunges into chaos. All Islands of Personality are destroyed and fall into it one by one. Much of Imagination Land is toppled down and disposed of in the dump. Bing Bong and even Joy end up in it. Bing Bong sacrificed himself so that Joy could come out from it.