Complex sentence: Point Lookout Lighthouse is a lighthouse that marks the entrance to the Potomac River, in Scotland, Saint Mary's County, Maryland, at the southern-most tip of the western shore of the Chesapeake Bay.
Split into simpler sentences: Point Lookout Lighthouse is a lighthouse that marks the entrance to the Potomac River, in Scotland, Saint Mary's County, Maryland. It is on the southern-most tip of the western shore of the Chesapeake Bay.