This is Buenos Aires' oldest neighborhood and even today, very little of the cityscape there is less than a hundred years old (except along Belgrano Avenue), thereby making a nearly seamless transition to the likewise historic San Telmo district, to the south.

The small city's growing population led to the introduction of a number of other religious orders in this area, notably the Catalan Brotherhood of the Virgin of Montserrat, whose chapel became the neighborhood namesake in 1769.

Little changed over the next seventy years, Monserrat's muddy shore and typically colonial grid of cobblestone streets came under a rapid modernization following Argentina's sudden economic development after 1875.

The area's led central location and its presence therein of much of Argentina's governmental structure led to monumental construction over the next twenty years, notable among which are the Buenos Aires City Legislature, the Customs building, the offices of La Prensa (today the Buenos Aires House of Culture), the art-deco NH City Hotel (off the Plaza de Mayo), the Ministry of Defense and South Diagonal Avenue.

Its rich architectural history and quaint, narrow streets have, as in neighboring San Telmo, helped lead to renewed interest in Monserrat since around 1990, a change highlighted by the 1993 opening of the high-rise InterContinental Hotel.