Heyang County (simplified Chinese: 合阳县; traditional Chinese: 合陽縣; pinyin: Héyáng Xiàn, 郃陽) is a county in Shaanxi Province, China, bordering Shanxi Province to the east across the Yellow River. It is under the administration of the prefecture-level city of Weinan.
Heyang County dates to at least the early Han, when Liu Bang's elder brother Liu Xi was demoted to being its marquess after fleeing a Xiongnu attack on Dai c. 200 BC.
A species of stone loach, Triplophysa heyangensis, is named after Heyang County where it was first discovered.[1]
As 2016, this county is divided to 12 towns.[2]