The Sure River is one of four main rivers in Luxembourg; the others are the Alzette, the Moselle, and the Our. The Sure rises in southeastern Belgium, then cuts across Luxembourg, flowing west to east, emptying into the Moselle at Wasserbillig. It is dammed just west of Esch-sur-Sure in central Luxembourg, forming a lake, and the Upper Sure National Park. The Sure forms part of the border between Luxembourg and Germany, between Reisdorf and Wasserbillig.
The Our is a major tributary of the Sure, joining it at Reisdorf.