Mecklenburg Castle, Medieval castle ruins in Dorf Mecklenburg, Germany.

Mecklenburg Castle is a medieval fortification on a small peninsula south of Wismar Bay, in the village of Dorf Mecklenburg, Germany. The site survives mainly as earthen walls that still outline the original layout of the stronghold.

Excavations point to a first castle built in the 7th or 8th century on a lowland at the tip of a lakeland peninsula, possibly the Obotrite residence of Reric destroyed in 808. By 965 the traveller Ibrahim Ibn Jacub called it Nakon's Castle, seat of the Nakonid princes. Otto III's charter of 10 September 995 first records the name Michelenburg. Niklot burned it in 1160; Johann I of Mecklenburg had it demolished in 1256 for building material for Wismar, and after a short rebuild in 1277 it was destroyed for good 45 years later.

The name derives from Old Saxon mikil (large) and Burg (castle), recorded as Michelenburg in a 995 charter of Otto III; the Slavic name was probably Wiligrad, also meaning large castle. That name passed to the duchy and region. The boulder by the wall bears the carved words BURG and MECKLENBURG.

The site is reached via Am Burgwall street, and information boards along the way help visitors follow the layout of the old fortification. Walking shoes are a good idea since the ground is uneven in places.

Since 1870 the old castle grounds have also served as the village cemetery, making this one of the few places where a medieval earthwork and an active burial ground share the same space. Visitors walking through the site move between centuries without any clear boundary between the two.