Since its establishment in 1848, it has been highly important and influential in the history and culture of ethnic Chinese immigrants in North America. Chinatown is an enclave that continues to retain its own customs, languages, places of worship, social clubs, and identity. There are two hospitals, numerous parks and squares, a post office, and other infrastructure. While recent immigrants and the elderly choose to live here because of the availability of affordable housing and their familiarity with the culture, the place is also a major tourist attraction, drawing more visitors annually than the Golden Gate Bridge.
According to the San Francisco Planning Department, Chinatown is "the most densely populated urban area west of Manhattan", with 34,557 residents living in 20 square blocks. In the 1970s, the population density in Chinatown was seven times the San Francisco average.
During the time from 2009 to 2013, the median household income was $20,000 - compared to $76,000 citywide - with 29% of residents below the national poverty threshold. The median age was 50 years, the oldest of any neighborhood. As of 2015, two thirds of the residents lived in one of Chinatown's 105 single room occupancy hotels (SRO), 96 of which had private owners and nine were owned by nonprofits. There are two public housing projects in Chinatown, Ping Yuen and North Ping Yuen.
Most residents are monolingual speakers of Mandarin or Cantonese; in 2015, only 14% of households in the SROs were headed by a person that spoke English fluently. The areas of Stockton and Washington Streets and Jackson and Kearny Streets in Chinatown are almost entirely Chinese or Asian, with blocks ranging from 93% to 100% Asian.
Many of those Chinese immigrants who gain some wealth while living in Chinatown leave it for the Richmond District, the Sunset District or the suburbs
According to wikipedia