Madiun is a city in the western part of East Java, known for its agricultural center. It was formerly (until 2010) the capital of the Madiun Regency, but is now administratively separated from the regency.
Madiun, located 169 km south west of Surabaya, covers an area of 33.92 sq. km, and had a population of 170,964 at the 2010 Census; the latest official estimate (as at 2014) is 175,767. This town is an average of 63 metres above sea level and lies on the Madiun River, a tributary of the Bengawan Solo River. It is surrounded by a number of mountains, including Mount Wilis (2,169 m) to the east, to the south the Kapur Selatan range (500–1000 m) and to the west Mount Lawu (3,285 m). Madiun has an average temperature of 20-35 degrees Celsius.
Madiun was the site of a noted uprising in 1948 by elements of the Communist Party of Indonesia (PKI), the "Madiun Affair". After the signing of the Renville Agreement that year, guerrilla units and militias under the influence of PKI were ordered to disband. In Madiun a group of PKI militia refused to disarm and were killed in September. The killings sparked a violent uprising. Army sources claimed that the PKI had announced the proclamation of the "Soviet Republic of Indonesia" on 18 September with Muso as its president and Amir Sjarifuddin as its prime minister.
The uprising was suppressed by republican troops. On 30 September, Madiun was taken over by republican troops of the Silwangi Division. Thousands of party cadres were killed and 36,000 were imprisoned. Amongst the executed PKi members were several leaders including Muso killed on 31 October, allegedly while trying to escape from prison. Other PKI leaders such as D.N. Aidit went into exile in China.