Maarsen. Maarssen is a town in the middle of the Netherlands, in the province of Utrecht, along the river Vecht and the Amsterdam-Rhine Canal. The west of Maarssen is called Maarssen-Broek whereas the east is called Maarssen-Dorp. Both put together and joined by other small towns around provide the area of Maarssen. On 1 January 2011 Maarssen merged with the councils of Breukelen and Loenen to become Stichtse Vecht. The former municipality of Maarssen consisted of the following cities, towns, villages and/or districts: Maarssen and Maarssen-Broek, Maarssenbroek, Maarsseveen, Molenpolder, Oud-Maarsseveen, Oud-Zuilen and Tienhoven.