Spring Point Ledge Lighthouse in south Portland (Maine) was built in 1896-7 to mark a ledge at the entrance of Portland harbor. Though it appears to be part of the adjacent fort, Fort Preble constructed in 1808, the only thing they have in common is location at the entrance to the harbor. One to protect ships the other to destroy them. From Spring Point Lighthouse you can see Portland Head Lighthouse 3 to 4 miles to the south. If you should stop by to visit the lighthouse be sure to check out the Museum.