Obviously, there can be no accurate count of illegal immingrants. Surprisingly, there are many countries with no accurate count of legal immigrants, either ...

[tag:germany]:

- [As of 2020][1], Germany had 5.2 million immigrants under EU freedom of movement. For these migrants registration is mostly a matter of tax law, and they can enter first, register only later when they find housing and work.
- 2.5 million immigrants had permanent residence status without EU freedom. That count is somewhat more certain. Some might have left without de-registering.
- 600 thousand had non-permanent residence status. e.g. student visa. Again a reasonably certain number.
- 2.0 million had various kinds of recognized refugee status. 
- 410 thousand had their immigration status under review.
- 780 thousand had their immigration request denied, but 
  - 450 thousand of those were permitted to stay temporarily and
  - 330 thousand were required to leave, yet approximately 80% of those were not required to leave immediately for various reasons. [This source][2] gives 45 thousand required to leave for 2020, which does not quite match 20% of 330 thousand but comes close.
- Then there are those whose presence is unknown to the authorities. For 2016 there was an [estimate][3] of half a million, but that number is highly controversial.

  [1]: https://www.bpb.de/kurz-knapp/zahlen-und-fakten/soziale-situation-in-deutschland/268959/aufenthaltsstatus-schutzstatus/
  [2]: https://mediendienst-integration.de/migration/irregulaere.html
  [3]: https://www.welt.de/wirtschaft/article154038484/Wie-sich-unregistrierte-Fluechtlinge-durchschlagen.html