The Causeway proper is a mass of basalt columns packed tightly together. The tops of the columns form stepping stones that lead from the cliff foot and disappear under the sea. Altogether there are 40,000 of these stone columns, mostly hexagonal but some with four, five, seven and eight sides. The tallest are about 40 feet high, and the solidified lava in the cliffs is 90 feet thick in places.
A fine circular walk will take you down to the Grand Causeway, past amphitheatres of stone columns and formations with fanciful names like the Honeycomb, the Wishing Well, the Giant's Granny and the King and his Nobles, past Port na Spaniagh where the Spanish Armada ship Girona foundered, past wooden staircase to Benbane Head and back along the cliff top.