The borders of the northernmost region of Croatia, Međimurje, were often changed during its turbulent past. It was this fact that has prompted the research of the reasons for these changes. The Međimurje region has experienced many changes throughout history, especially regarding state administrative belonging. This affiliation has changed over the centuries and greatly influenced the appearance of the present borders of Međimurje. Međimurje is a region that is conditioned by nature in its basics. It was, and still mostly is, a space inter Muram et Dravam. Precisely these two rivers had the key role in defining and changing the borders of Međimurje. The borders are described on the grounds of the existing literature and sources, using maps and other graphic attachments. The issue of the borders of Međimurje is still current today due to the fact that they were not fully defined and there are several border disputes with neighboring Slovenia, especially about the Mura border. After years of unsuccessful negotiations in 2011, it was decided that the border disputes were going to be dealt with at the arbitration court. Regardless of the arbitral tribunal’s decision, the author’s opinion is that the question of functionality of the border and the surrounding area must be of high priority for both sides, and that both sides should resolve that between themselves.