Milligersplas harbor Zwolle is located in the new urban district of Stadshagen. This district was built in the Mastenbroekerpolder, the oldest polder in the Netherlands. Stadshagen is the first residential area built across the Zwarte Water from the old city. Here is the Mastenbroek polder. This polder has hardly been affected since the 14th century's extraction. Since 2012, Stadshagen, together with the Westenholte and Spoolde districts, forms the Zwolle district West. On the spot where Stadshagen is now located, between 100 and 500 AD. a dense swamp forest. After this, the forest disappeared into a freshwater lake. Remnants of this forest were discovered in May 2000 during construction work on the edge of the Milligerplas. The area was reclaimed and drained in the 14th century.