This map by Benjamin Dearborn (1754-1838) is a proposal to construct what he called "Perpetual Tide Mills" across the Back Bay and South Bay in Boston. The plan details water and marshland as well as streets and roads of Boston, Roxbury, Brookline, Charlestown, Cambridge, Brighton, and Dorchester. Dearborn's map, which introduces an extensive series of canals, dams, and toll roads, is a variation on a previously proposed Mill Dam project. Creating a Mill Dam and road across the Back Bay came on the heels of the successful Mill Pond project near Boston's North End.

The aim of the Mill Dam was to use the tides of the Charles River to power mills for industrial purposes. Additionally, the Dam would serve as a toll road. In the end, Dearborn's plan was not realized and a much simpler Mill Dam was built by 1821. Eventually, this project failed in part because of sewage and wastewater build-up in the tidal basins. This build-up caused unpleasant smells that drifted all over the city. As a result, in May 1855, the Back Bay began to be filled in and developed.

Dearborn printed and colored the map using a letterpress, declaring that his plan "is probably one of the First ever Printed in a similar manner as the common Printing Press cannot be thus applied."