The history of Chinese immigration to Thailand dates back many centuries, and the specific Chinese ethnic groups which made their way to Thailand are numerous, although there is a greater concentration of Chinese from the southern provinces due to their geographic proximity to Thailand. The Chinese are part of the greater Sino-Tibetan ethnicity which also includes the Tibeto-Burmans. The Chinese immigrants were largely able to merge into the predominant Tai culture, and have contributed significantly to the economy and infrastructure of Thailand over the years.