All of East Prussia was initially supposed to go to Poland, until Stalin decided he wanted to use Königsberg as an ice-free port for the Soviet navy. In exchange, Stettin was transfered to Poland, even though it lay West of the Oder.
I have also read that once Stalin decided to annex northern East Prussia, it would have gone to Lithuania, except the the Lithuanian SSR's leadership didn't want it due to its devastation and depopulation.
I have also read that once Stalin decided to annex northern East Prussia, it would have gone to Lithuania, except the the Lithuanian SSR's leadership didn't want it due to its devastation and depopulation.