Komárom-Esztergom County
In the aftermath of World War I, the part of Esztergom county north of the Danube became part of newly formed Czechoslovakia, as recognized by the concerned states in 1920 by the Treaty of Trianon. The southern part remained in Hungary and merged with the southern part of Komárom county to form Komárom-Esztergom County in 1923.