The Garbage Dump is the area where the Pigmasks dump off every little piece of trash they have. There is a section for Claymen, and everything else goes all throughout the Garbage Dump. It's pretty big, but not bigger than...Tazmily. It's about half of that.
The Garbage Dump only appears in Mother 3, in Chapter 5. The only way to get here is by going through the Tower of Love. This is where they create Claymen. If there is a major failure, they will throw it out into the Garbage Dump. The Garbage Dump looks like a huge mess. It's barely organized. There are a few little gas stations and people roaming about, but nothing big.
Certain monsters such as the Reconstructed Robot lurk around this area. It is unknown how these came to life after the Pigmasks threw them away, and it is plainly unknown how the Road Signs came to life.