Locations are levels explored by Rion during the game and he will visit many of them. With the exception of the Uranium Refinery, are all in Michelangelo City or at least very close to it. In Galerians, once one location (known as a stage) is completed, Rion cannot return there anymore. In Galerians: Ash, each location instead is visited several times but they cannot be fully explored until certain points in the game. All areas in the games will have a viewable map aside from rare occasions (like the Mushroom Tower) where a map is not available.
They contain files, objects, and enemies. In Galerians, enemies are seldom replaced by others and only in Michelangelo Memorial Hospital. The amount of PPECs and drugs is limited and they do not respawn. In Galerians: Ash, by contrast, enemies respawn often until a certain amount have been killed. On some occasions, items will respawn upon revisiting the area.