Cycle path beside fjord. Google Street View

The most scenic run in central Porsgrunn is the path along the Porsgrunn River and Gunnekleivfjorden (fjord). Starting near the Porsgrunn City Hall (Rådhus) & Public Library, follow the Strandpromenade path headed west along the river south for 1 km, through the historic center of Porsgrunn, passing the Porsgrunn Bridge. Continue for another 1 km. Then, the path crosses the river and turns south, along the west side of the fjord. This is a nice, scenic 2.2 km section on a paved multi-use path. Turn around at the end of the path, just shy of the rotary, and retrace your steps.