Aigun (simplified Chinese: 瑷珲; traditional Chinese: 璦琿; pinyin: Ài Hún; Manchu: ᠠᡳ᠌ᡥᡡᠨ aihūn; Russian: Айгунь, romanized: Aigun) was a historic Chinese town in northern Manchuria, situated on the right bank of the Amur River, some 30 kilometres (19 mi) south (downstream) from the central urban area of Heihe (which is across the Amur from the mouth of the Zeya River and Blagoveschensk).
The Chinese name of the town, which literally means "Bright Jade", was a transliteration of the Manchu (or Ducher) name of the town. The current Mainland Chinese pronunciation Ài Huī does not reflect this, unlike the Taiwanese pronunciation which still follows the Old National Pronunciation Ài Hún.