Shimian County is both the southernmost and westernmost county in the prefecture-level city of Ya'an, Sichuan Province, China. The county seat, Miancheng Subdistrict (棉城街道), and the neighboring town, Xinmian (新棉镇), are often together referred to as Shimian. As of the 2010 census, Shimian County has a population of 123,600. The G5 Beijing–Kunming Expressway now passes through Shimian along the route between Kunming and Chengdu.

Ya'an is a prefecture-level city in the western part of Sichuan province, China, located just below the Tibetan Plateau. The city is home to Sichuan Agricultural University, the only 211 Project university and the largest regional comprehensive university in Ya'an. As of the 2020 Chinese census, Ya'an has a population of 1,434,603.