This 10 rod river is one of the „big guns” in the country and rarely if ever falls from the top ten listing. Each season 1.500 to 2.000 fish are taken. For five weeks each summer the river is fished by Americans, most of whom practice catch and release. Most of the catch in the Grimsa are grilse yet this river used to be one of the main haunts of larger salmon earlier in the century. The Grimsa is managed by the farmers themselves which is not a common practice when the main rivers are concerned in Iceland. The Grimsa has a small tributary, river Tungua, which is fished with two daily rods for two months per season. It usually pitches in with 50 to 80 salmon, which is not bad. A note of interest about the Grimsa concerns the lodge. It was designed by Ernst Schwiebert just above the waterfall Laxfoss. It is a controversial building and people tend to either love it or hate it.