Lithograph of the South Boston (or Boston South) bridge, circa 1820s *BPL Flickr group.
At the turn of the 19th Century, a group of land speculators who had developed parts of Beacon Hill looked south and east for another investment opportunity. Together, they purchased empty land across the South Bay on Dorchester Neck. This land was close to the Boston waterfront, but separated from Boston by a cove that reached south along Boston Neck to the towns of Roxbury and Dorchester. The investors then went to the state Legislature and got the land annexed to Boston - with no compensation to the Town of Dorchester! Sound like the Beacon Hill shenanigans we are so familiar with now are not a new phenomenon.
Hales, Map of Boston - 1819 (BPL).
With Dorchester Neck now South Boston, our speculators got permission to build a toll bridge to access their land, and open up development. The cove was still used for shipping - there were warves in Roxbury and along the Neck at the time - so their choice of construction locations was limited. They built the bridge from Dover street (now East Berkeley street) and Harrison avenue (that being the waterfront at the time. The Hales map shows Washington street - the original road through Boston Neck - and Harrison avenue (then Front street) running parallel, and Dover street a single block between them.
The get their money back, the investors set the toll higher than people were willing to pay, and eventually a free bridge was built to the north, cutting down the distance between Boston and South Boston. The bridge was sold to the city at a loss, but land in South Boston did become valuable for industrial use. In the end, the greatest use of the old South Boston bridge seems to have been as a place for young couples to stroll and look back at the city. That's what we see in the print above. Put yourself in the same place now, at the railroad yard running along the Southeast Expressway just across from the South End, and imagine being able to see the State House on Beacon Hill!
There is still a bridge at the same site, and as you cross it you can still see water from what is now the Fort Point Channel. The rest of the bay that once separated Boston from old Dorchester Neck has been filled, without the fanfare or romance that marks the same work done in the Back Bay.