Mariembourg is a town in Wallonia, Belgium. It is part of the municipality of Couvin in the Namur Province. The town is named after Mary of Hungary, governor of what was then the Habsburg Netherlands, who ordered the construction of a fortress town there in 1542. The fortifications were demolished in 1853, but the former arsenal remains. By 1554, it was conquered by French troops, and has throughout the centuries frequently switched hands. The town has a church (built in 1542), a Neo-Gothic former town hall and is served by a railway station.