Fossum Manor is located about eight miles north of the town of Skien, in earlier Gjerpen municipality. The main building was constructed in the period 1811 to 1818 and is in the French Empire style. Constructed of slagstone from Fossum Ironworks. The owner was then, vice regent Severin Løvenskiold. The main house has 60 rooms, including a large banqueting hall. Surrounding the main building is a beautiful park in English style.

Near the main building, we find one of the municipality's finest carvings. It is a field of agricultural carvings from the Bronze Age and show that there were settlements in the area about 3000 years ago.

Parts of Fossum were formerly church property, while much was farms that were acquired by Fossum Ironworks up through the ages, as well as farms and large stretches of forest around the Luksefjell and Sauherad Mountains. Fossum has been family owned since Løvenskiold 1739.