The lands that once belonged to the Commonwealth are now largely distributed among several central, eastern, and northern European countries: Poland (except western Poland), Lithuania, Latvia, Belarus, most of Ukraine, parts of Russia, southern half of Estonia, and smaller pieces in Slovakia and Moldova.

Two important ecclesiastical entities with high degree of autonomy within the Crown of Poland were Duchy of Siewierz and Prince-Bishopric of Warmia.

Just before the Union of Lublin (1569), four voivodeships (Kiev, Podlaskie, Bracław, and Wołyń) of the Grand Duchy of Lithuania were transferred to the Polish Crown by direct order of Sigismund II Augustus, and the Duchy of Livonia, acquired in 1561, became a condominium (joint domain) of both Lithuania and Poland.

His duchy, which had its capital in Königsberg (Kaliningrad), was established as a fief of the Crown of Poland, as had been Teutonic Prussia since the Second Peace of Thorn in October 1466.

This treaty had ended the War of the Cities or Thirteen Years' War and provided for the Order's cession of its rights over the western half of its territories to the Polish crown, which became the province of Royal Prussia, while the remaining part of the Order's land became a fief of the Kingdom of Poland (1385–1569).

[5] Following the territorial losses of the Second Partition of Poland, the Grodno Sejm of 1793 introduced a new administrative division (italic marks new voivodeships):[6] Thought was given at various times to the creation of a Grand Duchy of Ruthenia, particularly during the 1648 Cossack insurrection against Polish rule in Ukraine.

For similar reasons, plans for a Polish–Lithuanian–Muscovite Commonwealth also were never realized, although during the Polish–Muscovite War (1605–18) the Polish Prince (later, King) Władysław IV Waza was briefly elected Tsar of Muscovy.