Urriðafoss is Iceland's most voluminous waterfall, located in the Þjórsá River. It's a mighty sight with a flow of 360 m3/sec, dropping down by the edge of the Þjórsárhraun lava field. This impressive cascade is surrounded by serene and beautiful surroundings, making it a must-see stop off highway. It's also a popular spot for fishing but you do need a fishing licence if you are planning on doing that.