Zakerzonia (Ukrainian: Закерзоння, Trans-Curzonia; Polish: Zakerzonie) is an informal name for the territories of Poland to the west of the Curzon Line which used to have sizeable Ukrainian populations, and/or significant Lemko, Bojko and Carpatho-Rusyn populations before the invasion of Poland by the Soviet Union and Nazi Germany in 1939, and for this reasons were claimed to be enthically Ukrainian territories by Ukrainian nationalists in the aftermath of World War II.
"Zakerzonia" stands for "territory beyond the Curzon line", or in Ukrainian "Zakerzons'kyi krai". About 700,000 Ukrainians or Ukrainian language speakers lived in Poland after World War II within the new borders. They were a "demographic majority in many areas along a long border strip running from Chełm almost to Kraków".
The demography of Zakerzonia drastically changed by forcible resettlement of the Ukrainians, with major undertakings being the expulsion of Ukrainians from Poland to the Soviet Union (1944-1946) and Operation Vistula (1947).
- Timothy Snyder, "To Resolve the Ukrainian Problem Once and for All": The Ethnic Cleansing of Ukrainians in Poland 1943-1947, pp. 101, 104, 105, in Journal of Cold War Studies Vol. 1, No. 2, Spring 1999. http://www.yale.edu/history/faculty/documents/2ColdWarStudies.pdf
- Orest Subtelny, "The Fate of Poland's Ukrainians, 1944-1947", in: "Redrawing Nations: Ethnic Cleansing in East-Central Europe, 1944-1948", 2001, ISBN 0742510948
- Bohdan, Kordan. "Making Borders Stick: Population Transfer and Resettlement in the Trans-Curzon Territories, 1944–1949". International Migration Review Vol. 31, No. 3., 1997, pp. 704-720.