Rock Island is one of five state parks in Door County and is accessible via two ferryboats from Northport at the northern tip of the county. The only mode of transportation on the island is your own two feet — no cars, no trolleys, no bikes and no horses. The favorite destination for many day-trippers is the Pottawatomie Lighthouse, located about two miles from the boat landing. Built in 1836, it is the oldest lighthouse in the state and the third oldest on the Great Lakes. The park has 10 miles of hiking trails, 40 campsites, a nice beach and a lovely boathouse that is now part museum and part recreation center for visitors to the island.