A marshland is a type of terrain that is found in the Stronghold games. They are usually surrounded by trees.
Marshlands are swampy areas full of wet plantation, which slow people's movements. However, they are the source of valuable pitch, which can be used for military purposes or sold in the market.
Marshlands is the only type of terrain that pitch rigs can be placed on. These buildings are important, since only they can extract pitch from the swamps. After the pitchmen delivered pitch to the stockpile, it can be used for the castle's defense.