In service from the Civil War to World War II this was the main military installation of the Harbor Defense System. This 4,200-acre park includes 9 miles of paved bicycle and hiking trails. Other activities such as kayaking, camping, and swimming are popular here too. Don't forget to visit the shipwreck of the Peter Iredale which has been sitting in its current position since October 25, 1906. You can find it about two miles away from the parking lot.