She was married and later divorced from the late head of the House of Mecklenburg-Strelitz, Georg Alexander, Duke of Mecklenburg.

[1] Her father was the son of Archduke Joseph August of Austria who was one of the heads of the provisional government of Hungary following the removal of King Charles IV.

Ilona married Duke Georg Alexander of Mecklenburg civilly on 20 February 1946 and religiously on 30 April 1946 in Sigmaringen, Württemberg-Hohenzollern during the allied occupation of Germany.

[1] Her husband was the eldest child and heir of George, Duke of Mecklenburg, head of the House of Mecklenburg-Strelitz and his first wife Irina Mikhailovna Raievskya.

[citation needed] Ilona died in the morning of 12 January 2011 in Freiburg, Baden-Württemberg, Germany, aged 83.