Most of Boston’s brownstones were built in the 1800s as single-family homes. A brownstone is a townhouse but differs due to its exterior stone. The brownstone is a façade. When this stone is first cut it is pink but ages to the rich, chocolate-brown stone that sheaths the homes sitting high above the street.
The famous writer, Edith Wharton, lived in a brownstone and hated the identical facades of the townhouses. She described the brownstone as “hide-bound in its deadly uniformity of mean ugliness”.
Today, most people love the brownstone, however many are chopped up to make apartments or condos and the few that remain as single-family homes are very expensive.
There is brownstone around the door arch, however, the rest of the façade is brick.
View (1858) from State House dome westward along the Mill Dam (now Beacon Street), which separated Back Bay (left) from Charles River. (Source: Wikipedia) Note the brownstones in the foreground.