Highly detailed chart of Boston Harbor from Lynn Harbor and Nahant, south to Nantasket beach, Cohasset and Minot's Ledge Lighthouse.
Includes the numerous Boston Harbor islands, Broad Sound, out to The Graves, Thieves Ledge and Harding's Ledge, along with extensive sailing directions.
Lighthouses are indicated in red and include Egg Rock, Long Island Head, Narrows "Bug" Lighthouse, Boston Lighthouse, Minot's Ledge Lighthouse, etc. Also includes Life Boat Stations and Huts of Refuge of the Massachusetts Humane Society, and more. Also includes many roads, all shoals and bars, buoys, soundings in fathoms, and much more.
Eldridge and his son are probably best known as the compilers of Eldridge's Tide and Pilot Book, still in use today. His charts were compiled from their own surveys.
The map copyright indicates that it was copyrighted by Samuel T. Cushing in 1863.