The provinces of the Three Kingdoms realm. Traditionally, there were Nine Provinces (zhou): Qing, Yan, Yu, Yang, Jing, Liang, Yi, Ji, and Xu. Three more zhou were added to create the Twelve Provinces: You, Bing, and Ying. Unfortunately, no one historical source agrees with the names of the provinces. A province-level entity in the far south, known as Jiaozhou (Jiaozhi) was setup by Wang Mang (Xiong 2017, p. 617).
Throughout most of the Han Dynasty, twelve provinces existed except for Ying. Liang is referred to different names in the novel: Xiliang, Xizhou, Liang. We should be mindful that the novel was written and rewritten during the Ming and Qing periods and some references would reflect contemporary usage of the provinces names and not that of 3rd century China. The central metropolitan administrative region was known was Sili and had the two Han capitals Chang’an and Luoyang.
Sources:
Xiong, Victor Cunrui (2017). Historical Dictionary of Medieval China, 2nd Edition.
Yu Ninjie (2005). Map of Han Dynasty Zhou. Wikipedia, 2005. Accessed Jan. 2020 – https://commons.wikimedia.org/wiki/File:Han_provinces.jpg. Released under the GNU Free Documentation License, Version 1.2.