Zhong is pinyin transliteration of several Chinese surnames, including Zhōng 鍾/钟, Zhòng 种 and Zhòng 仲 etc. These are also transliterated as Tihon and Chung (especially in Vietnam, Taiwan, and Hong Kong).
Zhōng (鍾/钟) is the 54th most common last name in China. People surnamed Zhong are the descendents of Shang Tang. During the Zhou Dynasty, a descendent of Shang Tang, Wei Zi Qi was made the duke of Song (south of Shanqiu, Henan). A few generations later, Song Heng Gong had a son called Ao. Ao had a grandson Bo Zhong, who was a judge in the Jin kingdom. Bo pleaded for the duke of Jin to repent from his unrighteousness and was executed. His son Zhou Li fled to the kingdom of Chu and became the prime minister. He was awarded the land of Zhongli (northeast of Fengyang, Anhui), and his descendents were known as the Zhonglis. Among them, Zhongli Mei was a general under Xiang Yu. After Xiang Yu was defeated by Liu Bang, Zhongli Mei committed Suicide. Mei's son, Jie, fled to Zhangge, Henan, and changed his last name to Zhong. Zhong Jie can be considered as the forefather of the Zhong family.