Started when Prince Adipati Antakusuma leaving the kingdom of Banjar towards the west in order to find a place where it will set up a new kingdom. With the blessing from King and Queen, Prince Adipati, along with a number of guards, with sailboats heading towards the West. On the way, a lot of places visited, among others: the Sebangau Gulf, Pagatan Mendawai, Sampit, Kuala Pembuang and finally comes to a Pandau village inhabited by the Dayak Arut community under the leadership of Demat officer, in Umpang.

Prince Adipati Antakusuma is accepted by the Dayak Arut community to be the king of the Dayak people on the condition that the King should not be treated Dayak people as his servant , but as his top aides and close friends or a good brother. The People will not bow down to worship the Prince Adipati Antakusuma. That condition accepted by Prince Adipati, including the requirement of stamped agreement with human blood is by one of a Dayak tribe and one from Prince Adipati group.

Before sacrifice, the two people representing each side, took a stone to be plugged in to the ground as evidence of heredity, the witness of all time, through the ceremonies, the stone now known as the “BATU PETAHAN” in Pandau, North Arut District.

At the ceremony, the one that represent the Dyak tribes facing upstream where they place belong, while the one represent the group of Prince Adipati facing downstream, likens their arrival. Oat Ceremonial / covenant was eventually named “ PANTI DARAH JANJI SEMAYA”.

Since the Dutch recognized Indonesian sovereignty on December 17, 1949, by Law no. 22 In 1949, established a Kotawaringin regency with the capital Sampit, led by the District Head: Tjilik Riwut. Autonomous Region Kotawaringin at the time only in a level if kewedanan with the capital Pangkalan Bun with Wedana / Deputy Head, who was named: BASRI.

After a few years this area was within the Kotawaringin regency , on the basis of the will of its people were channeled through political parties, regional Swapraja Kotawaringin / Kewedanan Pangkalan Bun asked to separate themselves from the regency and the elimination swaparaja Kotawaringin into its own regency.

Then came the messenger of the parliament (DPR) to Pangkalan Bun, aim for a close look at where the region and the community, especially about the desire that animates the motion to estabilish its own regency. Once satisfied that the motion is really the desire of society, the central government issued Law no. 27 about about the solving of Kotawaringin regency become Level II Regional East Kotawaringin with Sampit as its Capital and Regional Level II West Kotawaringin with capital Pangkalan Bun.

At that time both the Regional Level (Dati) II has been in Central Kalimantan. Furthermore, on October 3, 1959 on behalf of theMinister of Home Affairs, Governor Tjilik Riwut inaugurated the West Kotawaringin regency in CENTER SEMBAGA MAS, Pangkalan Bun, and as the first regent is: C . MIHING.