Going stateside?
Stateside is just a cool word. But first some background.
Spacial relations are sometimes said to involve a figure and a ground, or alternatively, a trajector and a landmark. If my bike is in front of library, then the bike is the profiled figure with respect to the ground of the library. Similarly for we are under that airplane, we are the figure with respect to the airplane, which the the ground against which we are determining our location. Given this, then prepositions like inside and under are analyzed as determining exactly what sort of spacial relation holds between the figure and the ground: containment (inside, outside), vertical position (over, under), physical contact (on), and so forth. There are of course some more complex prepositions, like astride, diagonal, and opposite (not to say that the semantics of something like over isn’t complicated as all get out). For these guys, the spacial relation is more specific that something like at or near.
There are some words that express very similar meanings, but are not prepositions: deictics like there and here, and directional adverbs like away and up similarly express relations between a figure and a ground. These can also get somewhat complex, such as by incorporating the ground into their meanings. Examples of this are underground, above-ground, and underwater. In their adverbial uses, these basically have the distribution of other locative phrases (including preposition phrases and deictics): go/live/send it underground. They also have adjectival uses, as in underground facility/earthquake.
A very cool example of this sort of locative meaning is the word stateside. The word is attested from the mid 1940s, and seems to have become popular (and perhaps coined) during World War II. Its distribution is very similar to, say, underwater, but instead of incorporating a very generic ground (in this case, water), it incorporates “the United states” as its ground.* Thus we can go/return/send something stateside, and also talk about stateside resentment/policy/breakthroughs. The word doesn’t actually refer to the US as a nation-state or pseudo-agentive entity: we can talk about the American missile attack on strategic overseas military facilities, but not *?the stateside missile attack on overseas facilities. In this it is parallel to underwater, which also doesn’t refer to water per se, but rather a spacial relation between some object and water.