The Back Bay gained its name because the area was, in fact, before it was filled in, literally a bay. As with all of the New England coast, the bay was tidal, with water rising and falling several feet over the course of the day. At low water, part of the bottom of the bay was exposed.

In 1814, the Boston and Roxbury Mill Corporation was chartered to construct a mill dam, which would also serve as a toll road connecting Boston to Watertown, bypassing Boston Neck. The dam was later buried under present-day Beacon Street.

The Back Bay neighborhood was created when a parcel of land was created by filling the tidewater flats of the Charles River. This massive project was begun in 1857. The filling of present-day Back Bay was completed by 1882; filling reached Kenmore Square in 1890, and finished in the Fens in 1900. The project was the largest of a number of land reclamation projects, beginning in 1820, which, over the course of time, more than doubled the size of the original Boston peninsula.

Back Bay's development was planned by architect Arthur Gilman with Gridley James Fox Bryant. Strict regulations produced a uniform and well-integrated architecture, consisting mostly of dignified three- and four-story residential victorian brownstones. Greatly influenced by Haussmann's renovation of Paris in the mid-to-late 19th century, the main thoroughfares of Back Bay emphasize order, with wide, parallel, tree-lined avenues and homogenous architectural styles.

Today, the Back Bay is one of Boston's most beautiful and walkable areas, featuring stately brownstones and spacious, shady promenades. One of the most desirable and fashionable neighborhoods in the city, the Back Bay is home to upscale shops, sidewalk cafes, exotic florists, hotels, art galleries and people from all corners of the world. Many of Boston's best restaurants, hotels, shopping and night life, can be found in the Back Bay.