Ergun (Chinese: 额尔古纳市, É'ěrgǔnà Shì; Mongolian: Эргүн, Ergün), formerly Ergun Right Banner (Chinese: 额尔古纳右旗; pinyin: E'erguna You Qi), is a county-level city in China's autonomous region of Inner Mongolia. Administratively, Ergun is part of the prefecture-level city of Hulunbuir. It occupies 28,400 km² on the right (south-eastern) bank of the Argun River, which forms China's border with Russia's Zabaykalsky Krai (formerly, Chita Oblast).
The county-level city had the population of 85162 people as of 2006.