Guyuan is a prefecture-level city in the Ningxia Hui Autonomous Region of China. It was formerly known as Xihaigu or Dayuan (大原). The city occupies the southernmost section of Ningxia, bordering Gansu province to the east, south, and due west.
Guyuan is the site of the Mount Sumeru Grottoes (须弥山), which is counted among the ten most famous grottoes in China.
At the end of 2018, the total resident population of Guyuan was 1,124,200. By the end of 2024, the resident population was 1,140,800, a decrease of 6,900 compared with the end of the previous year. Of that total, the urban resident population was 535,600, accounting for 46.95 percent of the resident population, an increase of 1.29 percentage points over the end of the previous year.