Chinatown

Chinatown (Chinese: 唐人街) is the catch-all name for an ethnic enclave of Chinese people located outside Greater China, most often in an urban setting. Areas known as "Chinatown" exist throughout the world, including Europe, Asia, Africa, Oceania, and the Americas.
The development of most Chinatowns typically resulted from human migration to an area without any or with few Chinese residents. Binondo in Manila, established in 1594, is recognized as the world's oldest Chinatown. Notable early examples outside Asia include San Francisco's Chinatown in the United States and Melbourne's Chinatown in Australia, which were founded in the early 1850s during the California and Victoria gold rushes, respectively. A more modern example, in Montville, Connecticut, was caused by the displacement of Chinese workers in New York's Manhattan Chinatown following the September 11th attacks in 2001.
Definition
Oxford Dictionaries defines "Chinatown" as "... a district of any non-Asian town, especially a city or seaport, in which the population is predominantly of Chinese origin". However, some Chinatowns may have little to do with China. Some "Vietnamese" enclaves are in fact a city's "second Chinatown", and some Chinatowns are in fact pan-Asian, meaning they could also be counted as a Koreatown or Little India. One example includes Asiatown in Cleveland, Ohio. It was initially referred to as a Chinatown but was subsequently renamed due to the influx of non-Chinese Asian Americans who opened businesses there. Today the district acts as a unifying factor for the Chinese, Taiwanese, Korean, Japanese, Filipino, Indian, Vietnamese, Cambodian, Laotian, Nepalese and Thai communities of Cleveland. 
Further ambiguities with the term can include Chinese ethnoburbs which by definition are "... suburban ethnic clusters of residential areas and business districts in large metropolitan areas.

 An article in The New York Times blurs the line further by categorizing very different Chinatowns such as Chinatown, Manhattan, which exists in an urban setting as "traditional"; Monterey Park's Chinatown, which exists in a "suburban" setting (and labeled as such); and Austin, Texas's Chinatown, which is in essence a "fabricated" Chinese-themed mall. This contrasts with narrower definitions, where the term only described Chinatown in a city setting. 
History
Trading centers populated predominantly by Chinese men and their native spouses have long existed throughout Southeast Asia. Emigration to other parts of the world from China accelerated in the 1860s with the signing of the Treaty of Peking (1860), which opened China's borders to free movement. Early emigrants came primarily from the coastal provinces of Guangdong (Canton, Kwangtung) and Fujian (Fukien, Hokkien) in southeastern China – where the people generally speak Toishanese, Cantonese, Hakka, Teochew (Chiuchow) and Hokkien. In the late 19th century and early 20th century, a significant amount of Chinese emigration to North America originated from four counties called Sze Yup, located west of the Pearl River Delta in Guangdong province, making Toishanese a dominant variety of the Chinese language spoken in Chinatowns in Canada and the United States.
As conditions in China have improved in recent decades, many Chinatowns have lost their initial mission, which was to provide a transitional place into a new culture. As net migration has slowed into them, the smaller Chinatowns have slowly decayed, often to the point of becoming purely historical and no longer serving as ethnic Enclaves.

Chinatown - Wikipedia