The area was once a working class neighborhood for mostly German immigrants and home to semi-industrial enterprises such as a dairy and an automobile repair shop.

Prather's Alley, which was once lined with dwellings, stables, and industrial businesses, is being redeveloped into a place for community residents to gather.

[5] Prior to the Civil War the present-day Mount Vernon Triangle neighborhood was composed of simple frame dwellings occupied by tradespeople.

[6][7] The Northern Liberties Market on Mount Vernon Square, built in 1845, slowly increased development in the neighborhood, mostly along I Street and Massachusetts Avenue.

The Northern Liberty Market opened in 1875 with 284 vending stalls and had a profound effect on development in Mount Vernon Triangle.

The Italianate pair of buildings at 444 and 446 K Street, constructed in 1874, housed working class people, including immigrants from Russia, Austria, Germany, Ireland, and England.

John E. Wyess, a prominent German immigrant, built a Second Empire style house at 453 I Street as an investment property.

Instead of blocks of middle class rowhouses, most of the buildings constructed in the historic district and surrounding neighborhood were single or adjoining homes, light industrial facilities, or small commercial structures.

[2][6] The historic district's surviving buildings from the 1880s include an Italianate house at 468 K Street, constructed for Joseph A. Baur in 1883 and designed by John Beha.

Baur operated a stove store around the corner at 931 5th Street, one of three adjoining Italianate buildings constructed in 1883 and 1885 by John McDermott, a carriage builder and real estate developer.

In 1887 Charles W. King, a speculative real estate developer, built three adjoining Queen Anne style rowhouses on what was considered a nicer area of the neighborhood, Massachusetts Avenue.

Edmonston and his nephew Samuel were responsible for building several prominent homes in the city, including the adjoining Hay-Adams House for John Hay and Henry Adams, now the site of the Hay–Adams Hotel, and the Sherman mansion, now the Embassy of Kazakhstan.

He chose German architect Julius Germuiller to design his new 5,000 square feet (465 sq m) bottling plant, where he ran his business until 1925.

The building housed workers at his plant unlike the Romanesque Revival 462 K Street, also designed by Germuiller, that was constructed in 1906 and catered to middle class residents.

[2] The increase in automobile usage and location between two major avenues resulted in many residential buildings in the Mount Vernon Triangle being demolished and replaced with gas stations and repair shops.

The Wittlin-Deckelbaum Building, at 500-506 K Street NW and catty-corner to the Northern Liberty Market, offered modern amenities including central electric refrigeration and a temperature-controlled meat cutting sector and was an early example of the supermarket.

Many of the remaining buildings in Mount Vernon Triangle were demolished and replaced with parking lots after streetcar service on New York Avenue ended in 1949.

[2][6] In the late 20th century and early 2000s Mount Vernon Triangle had a reputation for being home to prostitutes, derelict buildings, and parking lots.

[9] While the Walter E. Washington Convention Center near the neighborhood's western edge was being built, community and local business leaders put forth a plan to redevelop Mount Vernon Triangle.

"[2] In 2014, two of the contributing buildings in the historic district, 470 and 472 K Street NW, collapsed and caused damage to the adjoining strip club.