Osfossen is a waterfall in Osen, Gaular. This waterfall is among the most known waterfalls in the Gaular Watercourse and is easily located by highway 610.
Norways oldest salmon stairs, which was build in 1870, is located on the southside of the waterfall. The stair is most likely the third oldest sculptures staircase in the world. The stair was constructed by the Irish salmids William T. Potts in cooperation with the fisheries consultant Carl Bruun. The stair is blowned out in the rock and brings the fish up in a fall of 11,5 meters, the length of the stair is about 45 meters.