Mamer is a commune and town located in south-western Luxembourg. It is situated approximately 7 km (4.3 mi) west of the capital city, Luxembourg City.
The commune comprises the town of Mamer as well as the smaller communities of Capellen and Holzem. Geographically, it is positioned on the river Mamer, which serves as a tributary of the Alzette river.
The area is notable for its infrastructure, as it is served by the A6 motorway connecting Luxembourg to Brussels. This roadway is also designated as European route E25.