Mianning County has a long history of being a multi-ethnic region.

The Annals of Mianning County (冕宁县志), published during the reign of the Xianfeng Emperor (1850-1861), listed a number of major ethnic groups in the region, including the Tosu, Lizu, Yi, and the Namuzi peoples.

[5] A large number of the Tosu ethnic group, which comprises about 2,000 people, live throughout Mianning County.

[2] Sizable clusters of Tosu people are located within Gaoyang Subdistrict, the former town of Houshan (后山镇, now part of Shilong), Fuxing, Hui'an, the former township of Haha (哈哈乡, now part of Gaoyang Subdistrict and Ruoshui), the former township of Linli (林里乡, now part of Fuxing), and the former town of Shaba (沙坝镇, now part of Manshuiwan).

[6] A 2013 survey found nine partial speakers of the Tosu language, all of whom lived in Mianning County, and were proficient in Southwestern Mandarin, which they used for daily life.