My great-grandmother is a Hakka in Meiyuan (near Siyi), Tiantou Village, Chixi County. Does anyone know this place?

According to your description, it should be in the following places:

Chixiwei Neighborhood Committee, located in Chixi Town, Taishan City, Guangdong Province, was formed by the merger of Chixiwei and Hotouwei. Total population 1 100, a total of 426 households. The distance from Chixiwei to Tiantouwei is 14 km, and Tiantouwei is the location of Chixi Town.

Chixi County is an abandoned county in Guangdong Province. It is located 35 kilometers west of Taicheng Town. In February of the sixth year of Tongzhi in Qing Dynasty (1867), "aborigines" fought with "Hakkas". In order to reduce conflicts, the authorities set aside most of Chaozhou Prefecture and a small part of Du Yao where "Hakkas" live from Xinning County, and set up Chixi Hall, which is directly under the Chief Secretary of Guangdong and Guangxi. The water here contains sediment and is colorful, hence the name "Chixitang". After the Republic of China, the hall was changed to the county organizational system, called Chixi County, with today's Chixi City as the county seat. 1953 was withdrawn from the county and put under the jurisdiction of Taishan county, renamed as "19 district". 1958 begins with Chixi Township; The second half of 1958 is called Chixi Commune; 1984 is called Chixi District; 1986 12 months later, it was called Chixi Town.