Cao Pi later ended the Eastern Han Dynasty by forcing Emperor Xian to abdicate the throne to him, after which he became emperor and established the state of Cao Wei, marking the start of the Three Kingdoms period. In Wei, Meng Da received various important appointments and the title of a marquis. Cao Pi merged the three commanderies of Fangling, Shangyong and Xicheng () to form a larger commandery, Xincheng (), and he appointed Meng Da as the Administrator () of Xincheng and tasked him with defending Wei's southwestern border. Meng Da became close friends with the Wei officials Huan Jie and Xiahou Shang.