The province has an area of 147,307 km² with a recorded 2010 census population of 4,395,983 . Ethnic groups include the Dayak, Malay, Chinese, Javanese, Bugis, and Madurese. The latest official estimate (as at January 2014) is 4,546,439.
The history of West Kalimantan can be dated back to 17th century. Dayaks were the main inhabitants of the province before 17th century. The Malay migrated to West Kalimantan and built their own sultanates. The high Chinese population in this province was due to a republic founded by Chinese miners called Lanfang Republic (蘭芳共和國: Republik Lanfang) after they defeated the local Malay sultans. The government of Lanfang Republic was ended in West Kalimantan after the Dutch occupation in 1884.
West Kalimantan was under Japanese occupation from 1942 to 1945, when Indonesia declared its Independence. During the Japanese occupation, more than 21,000 people in Pontianak (including sultans, men, women and children) were kidnapped, tortured and massacred by Japanese troops during the Pontianak incidents. All the Malay Sultans on Kalimantan were executed and the Malay elite was devastated by the Japanese.
The massacre occurred from April 23, 1943 to June 28, 1944 and most of the victims were buried in several giant wells in Mandor (88 km from Pontianak). Allied forces occupying the area after the war found several thousand bones, and more than 60 years after the massacre, several secret graves of the victims were found in Mandor and the surrounding areas.
After the end of war, the Japanese officers in Pontianak were arrested by allied troops and brought in front of an international military tribune. During the trial, it was revealed that the plan to start the rebellion did not exist and instead was only an imaginary plan created by Japanese officers who wanted to get promoted.
A monument called Makam Juang Mandor was created to commemorate this tragic event.
During the 1930s the Dutch colonial powers initiated a "transmigration plan" to move people from heavily populated islands such as Java, to the less populated islands of Irian Jaya and Kalimantan. In the 1960s the Indonesian government granted the Madurese rights to clear lands from forest for palm oil cultivation. This conflicted with the local Dayak tribes' traditional way of life. The tensions between the two ethnic groups resulted in major eruptions of violence in 1996, the Sambas riots in 1999 and the Sampit conflict in 2001, resulting in about thousands of deaths.