Between the Vistula and the Bug Rivers, the eastern border of Lesser Poland goes west of Leczna, but east of Krasnystaw and Szczebrzeszyn, both of which historically belong to Red Ruthenia. Further south, Lesser Poland includes Frampol, and Biłgoraj, which lie in the southeastern corner on Lesser Poland's historical Lublin Voivodeship, close to the border with Red Ruthenia. The border then goes west of Biłgoraj, turning south, towards Leżajsk (which belongs to Red Ruthenia). The boundary between Lesser Poland and Red Ruthenia was described by Ukrainian historian and geographer Myron Korduba as being along the line Dukla - Krosno - Domaradz - Czudec - Krzeszów nad Sanem. The border towns of Lesser Poland were: Rudnik, Kolbuszowa, Ropczyce, Sędziszów Małopolski, Strzyżów, Jasło, Gorlice, and Biecz. The southern border of Lesser Poland goes along the Carpathian Mountains, and, except in a few cases, it has not changed for centuries. The cities of Leżajsk, Rzeszów, Sanok, Brzozów, and Krosno do not belong to historical Lesser Poland, as they are part of Red Ruthenia (Lwów Voivodeship).