M�rsta is situated north of Steningevik, which is a bay of the lake M�laren. The center of the town is located in a valley called M�rstadal and the area S�tuna, which also holds the train station of the town.
The rest of the town's buildings spread upon and below the hills that form the valleys in M�rsta. The stream that flows through the town out to Steningevik is called M�rsta�n. It is also located along the motorway E4 about 37 km north of central Stockholm, 33 km south of Uppsala and about 4 km from Arlanda Airport
