Parts of Frønningen were owned by the Lem family as early as 1600. From 1650 they took over the entire Frønningen property. Throughout the centuries, they built and operated up to six water-powered ash saws, and operated extensively with the sale of timber.
In 1740 Hans Lem moved to Frønningen and built a large main house. After several generations of permanent owners, the last landowner of the Lem family, Hans Lem died childless in 1869. His sister was married to Jan Rumohr at Rikheim in Lærdal, who took over the operation of Frønningen. After Jan's death in 1890, his son, Bjarnard inherited the property.
1885 Rumohr built a large sawmill with more modern equipments and access roads. In 1900, Bjarnhard built a new main house after the old one was sold and moved to Voll in Lærdal. The new main house was built in a mix of Art Nouveau and neoclassicism, and is known as the "Storehouse".
The current owner is Bjarnhard's great-grandson, Vilhelm Rumohr, who also lives in the house.