What ever happened to Austrian Galicia? In the 1800's it was part of the Russian Empire, along with Polish regions.
More recent history:
Volhynia, the Northwestern section of modern Ukraine, was dominated by the USSR after WW I. From 1935-1938, Joseph Stalin had the Poles of Eastern Volhynia deported, the first of many forcible deportations of large groups. A little later, as reported in Wikipedia, we hear about massacres of Poles in Volhynia by the Ukrainian Insurgent Army (U.P.A.) during the Second World War, in the wake of the interwar oppression of the Ukrainians living in Polish territories, which followed the Polish-Ukrainian War in Galicia in 1918-1919, and the subsequent partition of Ukrainian lands between Poland and the USSR in the ‘Peace of Riga.’”
Wikipedia clarifies that Operation Wisla, [Akcja Wisla], named after the Vistula [Wisla] River, was actually organized to crush the anti-communist efforts of the Ukrainian underground. The Rusyn and Ukrainian populations that still existed in southeastern Poland were forcibly resettled to western and northern Poland, amidst a hostile population. The resettlement to West Poland occurred from April to July 1947, and involved about 130,000 – 140,000 persons who were internally relocated in Poland. Modern diplomats and historians call Operation Wisla an “ethnic cleansing.”
In modern Poland and Ukraine, there have been mutual attempts to apologize for deaths due to the guerrilla warfare from mid-1944 to 1950. Those who fought with either the U.P.A. or the O.U.N. (Organization of Ukrainian Nationalists) are now considered war veterans, entitled to military pensions. In 2007, the Security Service of Ukraine (SBU) set up a special working group to study archive documents of the activity of the OUN and UPA in order to make public original sources. [Most historians agree that these military groups were neutral regarding “the Jewish question.” They would either kill Jews or protect Jews depending on their political goals. A number of prominent Jews were active in each organization, often as medical personnel. The OUN produced “papers” legitimizing some Jews.]
Since 2006 the SBU has been actively involved in declassifying documents relating to the operations of Soviet security services and the history of the liberation movement in Ukraine. The SBU Information Center provides an opportunity for scholars to get acquainted with electronic copies of archive documents. The documents are arranged by topics (1932-1933 Holodomor, OUN/UPA Activities, Repression in Ukraine, Movement of Dissidents).