Norske Skog Union was a paper mill located in Skien in Norway.

In 1872 Ulrik Sinding had established a pulp mill beside the waterfall Damfossen in Skien.

In the years that followed Union acquired a lot of companies, in 1916 they bought Skiens Papirfabrikk on Klosterøya in addition to many pulp mills.

Cutbacks were soon implemented and in 2005 it was decided to close the mill, to large protests from the local population and politicians.

One primary complaint was that Norske Skog wanted to sell the mill despite it operating at a profit.