The establishment of Sun Moon Lake National Scenic Area was approved by Executive Yuan Letter Taipashipachiaotzu No. 47005 dated December 29, 1999, and MOTC Letter Chiaolupashihpa(1)tzu No. 067507 dated December 31, 1999. Theese letters detailed the operation and management scope of "Sun Moon Lake National Scenic Area," with a total area of approximately 9,000 hectares:
- Bound by Yuchi urban planning boundary to the north.
- Bound by the Shuishe Great Mountain ridgeline in the east.
- Bound by the boundaries of Shuili and Zhongliao townships in the west.
- Bound by Provincial Highway 21 and Shuili urban planning boundary to the south.
On January 24, 2000, "Sun Moon Lake National Scenic Area Administration" was established and placed in charge of the planning, construction, operation and management of Sun Moon Lake National Scenic Area. Later, in accordance with approved adjustments in Executive Yuan letter Yuantaichiaotzu No. 1000058178 dated October 7, 2011, and MOTC letter Chiaolu(1)tzu No. 1000012203 dated December 20, 2011, the operational and management scope was expanded based on the existing Sun Moon Lake National Park, centered on the current national scenic area but expanding to the north, west and south, with a total area of approximately 18,100 hectares.
- Expanded scope of the northern corner: bounded by Yuchi Township, Puli Township and Guoxing Township in the west, and Nangang River in Puli Township (excluding the forest compartment area) in the north.
- Expanded scope of the western corner: extends west along Qingshui River in the north to 100 meters north of Jiji branch railway line, bound by Jiji Township and Mingjian Township in the west, and extends to the Zhuoshui River area line in the south with the original line as the boundary.
- Expanded scope of the southern corner: to the east it is bound by the junction of Tannan, Dili and Shuanglong villages in Xinyi Township with the forest compartment boundary and Zhuoshui River as its boundary; it is also bounded by Shuanglong Mountain and Zhuogun River connecting Shuili and Xinyi Township on the south side.
The operational management scope was approved and adjusted by the Executive Yuan a second time with letter Yuantaichiaotzu No. 1090001225 on February 14, 2020, and announced by in MOTC Letter Chiaolu(1)tzu No. 10982003211 on July 14, 2020. The original operational scope included Yuchi Township, Shuili Township, Xinyi Township, Puli Township and Jiji Township in Nantou County. The adjustment added parts of Puli Township, Yuchi Township and Shuili Township, increasing the area from approximately 18,100 hectares to 19,100 hectares, including an increase of 570 hectares in Hutou Mountain and surrounding areas of Puli Township, an increase of 410 hectares in the Dongguang and Dalin area of Yuchi Township, and an increase of 20 hectares in the Shuili Railway Station area.
