"The area's boundaries are Market Street to the northwest, San Francisco Bay to the northeast, Mission Creek to the southeast, and Division Street, 13th Street and U.S. Route 101 (Central Freeway) to the southwest.^[4] It is the part of the city in which the street grid runs parallel and perpendicular to Market Street. The neighborhood includes many smaller sub-neighborhoods such as: South Park, Yerba Buena,^[5] South Beach, and Financial District South (part of the Financial District), and overlaps with several others, notably Mission Bay, and the Mission District.

As with many neighborhoods, the precise boundaries of the South of Market area are fuzzy and can vary widely depending on the authority cited. From 1848 until the construction of the Central Freeway in the 1950s, 9th Street (formerly known as Johnston Street) was the official (and generally recognized) boundary between SoMa and the Mission District.^[6][7] Since the 1950s, the boundary has been either 10th Street, 11th Street,^[8] or the Central Freeway. Similarly, the entire Mission Bay neighborhood may or may not be counted as part of SoMa,^[9] Excluding the entire Mission Bay neighborhood puts the southeastern boundary at Townsend. Redevelopment agencies, social service agencies, and community activists frequently exclude the more prosperous areas between the waterfront and 3rd Street. Some social service agencies and nonprofits count the economically distressed area around 6th, 7th, and 8th streets as part of the Mid-Market Corridor.^{[citation needed]}

The terms "South of Market" and "SoMa" refer to both a comparatively large district of the city^[10] as well as a much smaller neighborhood.^[11]

While many San Franciscans refer to the neighborhood by its full name, South of Market, there is a trend to shorten the name to SOMA or SoMa, probably^{[citation needed]} in reference to SoHo (South of Houston) in New York City, and, in turn, Soho in London.

Before being called South of Market this area was called "South of the Slot", a reference to the cable cars that ran up and down Market along the slots through which they gripped cables. While the cable cars have long since disappeared from Market Street, some "old timers" still refer to this area as "South of the Slot".^[8]

Since 1847^{[citation needed]}, the official name of the South of Market area has been the "100 Vara Survey" (alternately "100 Vara District") or simply "100 Vara" for short (with "100" sometimes spelled out). The "100 Vara Survey" derived its name from the surface area of the single lots which comprised 100 by 100 varas (275 square feet).^[12]

According to city documents from 1945,^[13] the "100 Vara District" goes from the south side of Market Street to the Ferry. The name is found mainly in history books, legal documents,^[14] title deeds, and civil engineering reports.^{[15] "}

Wikipedia.  Updated 9/2/2020.  Accessed 9/19/2020.  https://en.wikipedia.org/wiki/South_of_Market,_San_Francisco