Skógafoss is a waterfall situated on the Skógá River in the south of Iceland at the cliffs of the former coastline.
After the coastline had receded seaward (it is now at a distance of about 5 kilometres (3.1 miles) from Skógar), the former sea cliffs remained, parallel to the coast over hundreds of kilometres, creating together with some mountains a clear border between the coastal lowlands and the Highlands of Iceland.
Skógafoss is one of the biggest waterfalls in the country with a width of 25 metres (82 feet) and a drop of 60 m (200 ft).
Reference: Wikipedia