Eastern Borderlands or simply Borderlands was a term coined for the eastern part of the Second Polish Republic during the interwar period (1918–1939). Largely agricultural and extensively multi-ethnic with a Polish minority, it amounted to nearly half of the territory of interwar Poland. Historically situated in the eastern Polish–Lithuanian Commonwealth, following the 18th-century foreign partitions it was divided between the Empires of Russia and Austria-Hungary, and ceded to Poland in 1921 after the Treaty of Riga. As a result of the post-World War II border changes, all of the territory was ceded to the USSR, and none of it is in modern Poland.

Western Ukraine or West Ukraine refers to the western territories of Ukraine. There is no universally accepted definition of the territory's boundaries, but the contemporary Ukrainian administrative regions (oblasts) of Chernivtsi, Ivano-Frankivsk, Lviv, Ternopil and Zakarpattia are typically included. In addition, Volyn and Rivne Oblasts are also usually included. It is less common to include the Khmelnytskyi Oblasts in this category. It includes several historical regions such as Carpathian Ruthenia, Halychyna including Pokuttia, most of Volhynia, northern Bukovina and the Hertsa region, and Podolia. Western Ukraine is sometimes considered to include areas of eastern Volhynia, Podolia, and the small northern portion of Bessarabia.