The waterfall is located along the Norwegian National Road 9, just south of the village of Ose in the municipality of Bygland in Agder county.

The waterfall flows down into a short stream before emptying into the northern end of the Åraksfjorden.

[1] Reiårsfossen got its name because one of the workmen's sons, Reiår (old spelling for Reidar), had fallen in love with a farm girl in Ose.

[2] The waterfall has become a tourist attraction and there is a public campground, Camp Reiårsfossen, just to the east on the shores of the Åraksfjorden.

There is a full-year toll road to the top of the falls and further inland to the lake Reiårsvann.