What is the name of this unofficial, historical designation for the German state, in which the Frontier March of Posen-West was a province of the Free State of Prussia?
Posen-West Prussia: The Frontier March of Posen-West Prussia (German: "Grenzmark Posen-Westpreußen" , Polish: "Marchia Graniczna Poznańsko-Zachodniopruska" ) was a province of the Free State of Prussia within the German Weimar Republic. Weimar Republic: Weimar Republic (German: "Weimarer Republik" ] ) was an unofficial, historical designation for the German state between 1919 and 1933.
Weimar Republic