At its founding in 1630, the City of Boston was 738 acres. Most of that acreage clustered on the end of an isthmus so thin it was called the Boston Neck.
Today, Boston runs to more than 57,363 acres, the isthmus long gone.
Annexations caused a lot of that physical expansion, including of municipalities such as Charlestown, Dorchester, Roxbury, and Hyde Park. A lot of it, though, came from reclamation: rolling back the waterfront and filling it in with landmass.
Here are the most significant infills.
The Back Bay
No American city had attempted a reclamation on this scale when Boston in 1857, using gravel from Needham, commenced the infilling of 600-plus acres of tidal basin—literally the Back Bay.
The reclamation had its critics: Was it really necessary and how long would it take? (Twenty-five years, it turned out.) But the infill seemed increasingly necessary after sewage began backing up in the bay just west of the newly created Public Garden.
Plus, a dam that became Beacon Street and that fostered a bit of residential development had already gone up along the bay. It was a start.
The waters around South Boston
Once upon a time, South Boston was the pastoral outskirts of an independent Dorchester. In 1804, land speculators-slash-developers engineered its annexation to Boston.
At the time, South Boston was 579 acres. Within the next 106 years, it would grow through reclamation to 1,333 acres.
The expansion also meant the de facto creation of Fort Point Channel. Why? Because the neighboring South Bay shrank and shrank.
The damming of a cove in the 1700s to create water power for mills in turn created Mill Pond. But, like with the Back Bay, the body of water became a kind of de facto sewer, with Bostonians tossing garbage into the silty expanse (typical).
Plus, the water level started dropping and so therefore was its use as a power source. Landowners adjacent to the pond began filling in parts of it illegally, which prompted the pond’s proprietors to go ahead and do the whole thing.
They started in 1807 and wrapped in 1828, adding 50 acres to a growing Boston. The area is now known as the Bulfinch Triangle.
Incidentally, the project meant the decimation of Beacon Hill’s original summit, as fill from there was used to reclaim Mill Pond.
The coves and the South Bay
The infill of these wharf-lined waterfront areas increased Boston’s physical size dramatically throughout the 19th century.
The infill of what was called South Cove (think Chinatown today) and the Great Cove (think the Financial District) commenced in 1806 and continued into the 1840s. South Bay, which now includes a chunk of downtown Boston, started in the 1850s.
Much of the ballast for the cove infills came from what was known as Fort Hill—now Fort Point.
This corner of Boston was no stranger to reclamation projects when the U.S. Army built an airfield on 189 acres of reclaimed tidal basin after World War I.
Much of what we now call East Boston was created over a century and a half via the linkage of five islands that were mostly privately owned. The creation of the airfield—aka Logan Airport—topped it all off.
The first airplane touched down at the then-Boston Airport in 1923.