This is a small river with its sources at the 500 m elevation in the mountains. After the confluence of the two  main sources, Mularangalaa and Garpadalsrangalaa, the name Mulaa is used throughout the lake Garpadalavatn and from there to the sea in the Gilsfjordur bay.

The surroundings are well vegetated and beautiful. The main  road crosses the lower part of the river close to the farm Gilsfjardarmuli. The catch consists mainly of sea char, both in the river and the lake, and there are many good fishing spots in both. The distance from the capital is about 208 km  by the Whale Bay tunnel and about 55 km from Budardalur.