Zoigê County or Ruo'ergai County (Tibetan: མཛོད་དགེ་རྫོང་།, Wylie: mdzod dge rdzong, ZYPY: Zoigê Zong; Chinese: 若尔盖县; pinyin: Ruò'ěrgài Xiàn) is a county of Ngawa Tibetan and Qiang Autonomous Prefecture in Sichuan, China, bordering Gansu to the north.

The county is primarily a highland basin made up of the Zoigê Marsh between the Min Mountains and Amne Machin.

Snow can fall any time of the year and usually does not melt until summer due to repeated nightly freezing even when maxima are above 0 °C (32 °F).

Therefore, access to Ruo'ergai is heavily restricted during the winter months from late October to early May.

Sitting at an altitude of more than 11,000 feet, high-altitude sickness is another common problem for tourists.