The castle sits at the centre of the older half of town and is the place to start a walk through Mosonmagyaróvár. The core is medieval — a small fortress raised in the 13th century on the site of the Roman fort of Ad Flexum — but successive reconstructions have given it the look of a Renaissance manor with thick walls and a quiet inner courtyard.
The building has belonged to the local agricultural university since 1818, which has kept it from being polished into a tourist set-piece. You can walk into the courtyard for free during academic hours; the surrounding park is open year-round and is a pleasant place to picnic.