Coastal Lights addition. The Chesapeake Bay has been an important avenue of commerce since colonial times. This was particularly true in the age before railways and roads, when water was the most efficient means of mass transport. The 150+ mile long Chesapeake Bay is basically the sunken river valley of the Susquehanna River. Apart from a deep channel running up its center, the Bay is relatively shallow and has many shoals which pose a hazard to navigation. Lighthouses were critical to assiting ships. Of the 82 lighthouses that once marked Chesapeake Bay, 32 are still standing. Coordinates with 4025272 "A Salty Dog's Respite". Replacement bulb (56.53121).