The borders of modern Poland were defined in the aftermath of the Second World War and the establishment of the People's Republic of Poland. They were agreed in the field of international law by the Yalta Agreement of February 11, 1945 and the Potsdam Agreement of August 2, 1945. These agreements generally defined the course of borders, without setting them out in detail. Their specification and then demarcation in the field had to be normalized in bilateral agreements between the states concerned.
Major border crossings
After accession of Poland to the European Union in 2004, border crossings with EU states (Germany, Czech Republic, Slovakia and Lithuania) were made redundant. Infrastructure remains in place, but its systematic use and the controls are no longer allowed by the Schengen agreement.[3]
Historically, Poland also had borders (and border crossings) with former countries, or with countries that no longer share a common border with Poland:
^Ustawa z dnia 29 czerwca 2007 r. o zmianie ustawy o ochronie granicy państwowej oraz ustawy o zmianie ustawy o Straży Granicznej oraz niektórych innych ustaw. Dziennik Ustaw, 2007, numer 140. pozycja 982