Transit through US without being a resident of any country

Just to add to the good other answers and to pick up on a few things you said in the comments (and sorry, can’t comment, so also mentioning a few things in reply to comments right here):

• I’ll concur in the advice to keep things simple, even more so as you mentioned the BCO already has all the details. What you may need to be prepared to add (again in simple terms), where it doesn’t pass as obvious by itself, is to give the simple explanation about the details, the bigger picture about what you are really doing.

Which, as others have pointed out, should not sound like a person unreliable about where they live or about political issues – but none of these seem to really fit your case as what you are really doing seems quite simple and straightforward (and legal) so you should be perfectly fine.

• Most importantly, you are core mainland EU citizen (obviously, having a German passport) traveling with the intent to set up (if rather temporarily) in another EU country.

(Note that "to set up" is an imprecise term for a good reason – within the EU, you are not required to know your own plans any more precisely than that as – for border control considerations, you’re practically only moving in-country.)

*No idea why you are making a transfer inside the EU through the US but whatever. (Curious to know, though.)

Not only that’s the most legal thing for you to do in your position, it is legal to the extent that you don’t even need any kind of paperwork to do it – you just go and that’s it.[1] (FWIW it’s legal to the extent that you don’t even have any paperwork about it simple because none is required. Other than the German idea of registering your place of residence, which is largely really about municipal taxes and urban development.)

[1] Formally, for those not familiar with it, it’s called the Schengen Area and using that is roughly the same as going from one US state to another US state, inside the US (obviously), is for an US citizen.

which is a) perfectly legal, b) perfectly understandable if one is so inclined, c) should be perfectly meh to an INS officer and the like who would be looking for possible violations of immigration laws – something you neither intend nor would have any connection with your own plans.

Consistently with the above, on a side note,

• a "titre de sejour" is exactly what the OP would never need anywhere inside the EU, already being a Schengen Area citizen and that of the core countries such as Germany, France, Italy, Belgium, Spain etc. (@NicolasFormichella – no offense but quite confused that (being in Paris and looking Italian, no offense again) you wouldn’t know that.) A "titre de sejour" is a permit for EU aliens (non-citizens of the EU) asking to be legally living (for a usually limited, though often practically indeterminate given period of time) in the issuing country, other than on whatever visa.

On some other side notes,

• So it seems you have been around the world a lot, and obviously always within the legal (and never trying to stay in the US in any awkward way). No red flags to US immigration visible whatsoever.

• What’s a problem about world travel anyway? Australians, for one example, do it a lot, and so what? Can’t be unfamiliar to US BCOs.

• might could be your thinking is being a bit overly anal (as in detail-possessed) and getting caught up in that about what to say? If a form is asking information in a simplistic way, it’s not necessarily that the form is insufficient. Well maybe it is, but making you enter information in a crudely simplifying manner seems to suggest that doing so is considered sufficient for its purpose.

• As for the form entry specifically, when there is no such thing as "last" or "intended" country of residence, it might seem natural to think "natural country of residence" as in "citizenship"

Your German citizenship should preempt your residency for most requirements from the comments above

This. I guess that, if asked, would be something that could have legitimately seemed obvious to you even if for some reason you were not sure about the form. I mean, if the form isn’t asking something very specific (sorry and no offense about the form), what else could be the natural thing to enter?

You are temporarily not registered in Germany as living there on a municipal register level (which is arguably not even a category to a BCO I guess so no point in even bringing it up), so?

• Seems more interesting what would happen if you were stranded anywhere in the world and that country expelled you, where would you end up being? Being a German citizen, that would be Germany. End of question.

It seems unlikely to me that you would be confronted about entering the "wrong" choice in the form. If it did happened, it would be plausible (as is the case) that you were confused about details that are probably not even relevant (guess the BCO would know what should have been entered to give them the information they need?) your confusion could innocently come across as momentarily sheepish, but obviously innocent.

Seems to me (though not a thing to state) that restrictive forms to enter things in can be thought of as morons, either that or entities that just don’t care beyond the point of what you can enter. Also, if obviously no one there cares about more exact information (not having made it possible to even enter more exact information), it must be good enough to enter the information you can enter. "That form did not allow me to specify more, so I entered as much as it asked me to. That’s what it asked, so meh."

On a closing note, I feel curious to hear how it went – would you feel like following up with us?

I think you are confusing 3 different things:

• citizenship (nation who issues your passport and cannot refuse you entry to their borders even if they leave the EU)
• residency (the place you keep your core possessions and sleep at night when not traveling)
• some set of beliefs you hold – not to diminish them in any way, but we need to clear up the fact that these 3 things are not the same.

Confusing these, or perhaps more aptly to "take a political stand" on something – will only result in refusal. Refusal means no more visa waiver, and paying $160 to apply for a visa when/if you want to visit the US in the future, and the wait, and the need to explain your planned activities in greater detail.

Residency is a statement of fact, and facts obviously cannot be about future things that may or may not happen. Therefore, "where you have been staying up to this point" is the answer they are looking for. And stating a residency places you under no obligation to live there in the future.

You just can’t live here.

Immigration is keenly watchful for people who want to enter on a visitor visa or waiver, and then violate the terms of their visa by overstaying or seeking employment. If you even smell like a person like that, i.e. rootless, wandering, a continuous world traveler*… they have every reason to refuse you. As such, a powerful part of any visitor application is a showing if facts that you have roots in another country and thus strong incentive to return there when your stated business is done.

* unless you have an ocean-going boat and have arrived on it.

I’m adding this as an answer of what not to do, because you might not be aware of some fringe political/legal arguments people try to make in the US. There are people that refer to themselves as "Sovereign Citizens" and they talk about not being under the jurisdiction of any country’s laws so they can do things such as "freely travel" or "non-commercially transit" the country without a need for driver’s licenses, license plates on vehicles, etc. Basically they claim to be outside of the laws for any given city or state because they are their own country (or something like that).

This falls under the heading of "conspiracy theories" and if you want to research it, keep in mind that no legal entity in the US agrees with what they claim.

So, why bring it up? Well if you start telling officials that you don’t have a country of residency/jurisdiction and you should be free to travel, etc, you’re using some common phrases that might lump you in with this movement. It’s the first thing I thought of when you said "you’re not a resident of any country", but I’m probably biased from watching several videos about the sovereign citizen movement.

So, I agree with the other answers saying what you should do, but don’t go around saying you’re not a resident of any country without a little more explanation.

Based on the information in your question and in the comments, you are a resident of Germany for US immigration purposes. The US does not have a system equivalent to the German official residence registration and does not care about your Abmeldung. If you are a citizen of Germany, lived there relatively recently, and are not a permanent resident of any other country, you should choose Germany as your residence and, without lying, leave border officials with the impression that you have a plan to return there.

If you make yourself appear "interesting" to border officials, perhaps by insisting that you have no residence and no definitive plan to live anywhere, you will very much increase your chances of your entry to the US being delayed or denied.

You know, I have been a digital nomad before it was cool, around 2006-2008. And what I learned is the world is simply behind legislation wise and it is us who needs to adjust. Indeed, these days one could use a different visa created for this purpose every year from dozens of countries and never have a residence — or so it seems.

What I am leading to is this: we need to construct a narrative that is plausible, easily acceptable by authorities and somewhat defensible by us legally. Our realities simply do not fit the legislation. It’s severely behind. Do not fret too much just make sure you can make an argument if push comes to shove. Example: do you need to file a tax return this year in Germany? Great, you are a German resident.

Outside of edge cases (seafarer, etc.), you are a resident of a country. You legally become a resident as soon as you settle there for more than a few months (for work, study, etc.) and if you have the right to do so.

You left Germany to go to another country so, in that form, I’d put the country you’re currently living in.