According to the definition of metropolitan areas formerly used by the Republic of China government, Hsinchu metropolitan area (Chinese: 新竹都會區; pinyin: Xīnzhú Dūhuì Qū) includes the following areas:
However, since the December 25, 2010 readjustments of the municipalities (an adjustment that did not affect Hsinchu directly), the Republic of China government has abolished the definition as obsolete.
The population of the metro area in 2016 was almost 1,000,000, and when including Zhunan and Toufen and accounting for the rapid population growth of the area, estimates by 2016 are over 1.2 million.
References
Hsinchu metropolitan area Wikipedia(Text) CC BY-SA