The Hubei–Henan–Shaanxi Revolutionary Base Area, or the Eyushaan Revolutionary Base Area (simplified Chinese: 鄂豫陕革命根据地; traditional Chinese: 鄂豫陝革命根據地; pinyin: È-yù-shǎn Gémìng Gēnjùdì) was a Communist-controlled revolutionary base area (simplified Chinese: 革命根据地; traditional Chinese: 革命根據地; pinyin: gémìng gēnjùdì) in north-central China that existed from late 1934 to 1937. It was a constituent part of the Chinese Soviet Republic, a self-declared sovereign state within the Republic of China. The revolutionary base was located in the mountainous tri-provincial border region between Hubei, Henan, and Shaanxi, from which it gets its name. It spanned a contiguous area including parts of present-day Shiyan in Hubei, Sanmenxia and Nanyang in Henan, and Shangluo and Ankang, in Shaanxi.
Red Army forces first took the area on December 8, 1934, and declared the establishment of the revolutionary base area two days later. During its existence, the Eyushaan Revolutionary Base Area faced near-continuous attacks from the Nationalist army and local anti-communist guerillas. Following the Xi'an Incident, which helped create the Second United Front, Red Army forces from the area left the area to join the front lines against the Japanese invasion.
