At the bottom of Álftafjörður there is a waterfall in Seljalandsá which can be seen from the road.
Further into the valley there is a beautiful canyon called Valagil which has an impressive series of waterfalls in it, of which the top one is tallest. It’s about a 2km easy hike from a parking lot.
A little bit further west there is a waterfall above the farm of Minni-Hattardalur.