Svartå Bruk (Mustion Ruukki) is located at the offspring of Lohjanjärvi (Lojosjön). A small river with slow flowing water and minor rapids starts with water from Lohjanjärvi and flows all the way to Pohjanlahti. The river has a few powerplant dams where kayaks need to be carried around if going the full length of the river. The river stretches past agriculture areas for a distance of 24 kilometers. The tour may start and extend some of the distance to return back upstream to the startingpoint.