Yongxin County (simplified Chinese: 永新县; traditional Chinese: 永新縣; pinyin: Yǒngxīn Xiàn) is a county in the west of Jiangxi province, People's Republic of China, bordering Hunan province to the west.

The county was built in the ninth year of Jian'an in the Eastern Han dynasty that is, in 204 AD.

The name of the county was derived from Great Learning in the meaning of "the sun (日) is forever (永) and the moon (月) is new (新)".

[1] One of the villages in Yongxin, Sanwan Town, is known for the creation of the 1st regiment of the Chinese Red Army led by Mao Zedong with 1,000 soldiers that fled the Kuomintang after the failed Autumn Harvest Uprising in 1927.

According to the data of the Seventh National Population Census in 2020, the total resident population (Chinese: 常住人口) of the county was 393,984 (excluding active-duty soldiers of the People's Liberation Army, residents of Hong Kong, Macao and Taiwan and foreigners living in the district).