The desire to expand Deli Serdang Regency actually has been emerging for a long time among the people of Deli Serdang and in 1992 had become a separate study for the local government at that time. The basis consideration for expansion was because the area and the amount of the population was so large for a regency criteria. Studies on the division this region had reached the issuance of Decree of the Deli Serdang Regional Parliament Number 02/DPRD/1992 dated February 27, 1992 concerning the Approval of Regional Division of Deli Serdang which stipulated that Deli Serdang Regency was divided into 2 (two) regions, namely Deli Regency and Serdang Regency. But planning for the division was halted and resumed when the reformation took place in 1998.
The issuance of Law Number 22 of 1999 Concerning Regional Government Regulation Number 129 of 2000 Regarding the Requirements for the Formation and Criteria to Expand, Eliminate and Merger of Regions gave more open space for people's wishes to make expansion. Several society groups formed to support this expansion and those are: 1) The Serdang Bedagai Regency Expansion Support Board (BPPKDS) in 1992, 2) Deli Regency Establishment Committee (PPKD) in 1992, and 3) Committee for the formation of Serdang Bedagai Regency Expansion (P3KSB) 2002.
BPPKDS planned for Deli Serdang Regency to be divided into two regencies with the proposed capital of the expansion regency, among others: Dolok Masihul, Sei Rampah and Perbaungan. PPKD emphasized more on establishing a new regency was Deli Regency with the capital of Patumbak, but accordance that the purpose of the division was not apparent, instead of had a desire to separate from Deli Serdang Regency. P3KSB proposed the division of Deli Serdang Regency into 2 (two) regions, namely Deli Serdang Regency as the main regency and another one Serdang Bedagai Regency as the expansion region with the capital of Sei Rampah.
The overwhelming desire from the people was responded wisely by the Deli Serdang Government with set up the basic concepts of regency expansion and conducted studies was needed. Based on research and suggestion from various elements of the society, the Deli Serdang Regency Government proposes that the Deli Serdang Regency could be divided into 3 (three) regions, namely Deli Serdang Regency as the main regency, Deli Regency and Serdang Bedagai Regency as the expansion.
Through long journey of the expansion process, Deli Serdang Regency legally began by stipulated of Decree of the Deli Serdang Regional Parliament Number 13/KP/Year 2002 Date August 2, 2002 Concerning Approval for Establishment/Expansion of Deli Serdang Regency. Furthermore, North Sumatra Provincial Parliament through Decree Number 18/K/2002 dated August 21, 2002 stipulated the Approval to Expansion of Deli Serdang Regency. Deli Serdang Regency Parliament through Decree Number 26/K/DPRD/2003 dated March 9, 2003 established the Approval of Proposed Deli Serdang Regency Expansion Plan into 2 (two) regencies namely Deli Serdang Regency as the main regency and Serdang Bedagai as the expansion regency with the capital of Sei Rampah. The consideration of the name of Serdang Bedagai Regency was based on history in which this region was formerly within the territory of the Serdang Sultanate and the Bedagai Sultanate.
Following up on the decision, the Governor of North Sumatra through Letter Number 136/6777 dated August 30, 2002, continued the proposal to expand Deli Serdang, Nias and Toba Samosir Regency to the Minister of Home Affairs in Jakarta. Based on the approval of the Indonesian Parliament, the President of the Republic of Indonesia issued Law Number 36/2003 Concerning for Establishment of Samosir and Serdang Bedagai Regency in North Sumatra Province.
On January 6, 2004 the Minister of Home Affairs issued Decree Number 131.21-26 of 2004 Concerning the Appointment of Serdang Bedagai Regent in North Sumatra Province and Appointed Drs. H. Chairullah S.IP, MAP as a Regent of Serdang Bedagai. On behalf of the Minister of the Home Affairs on January 15, 2004 the Governor of North Sumatra Mr. T. Rizal Nurdin inducted Mr. Drs. H. Chairullah S.IP, MAP as acting Serdang Bedagai Regent.