Maguindanao del Sur, officially the Province of Maguindanao del Sur, is a landlocked province in the Philippines located in the Bangsamoro Autonomous Region in Muslim Mindanao in Mindanao. Its capital is the municipality of Buluan near the city of Tacurong in the neighboring province of Sultan Kudarat. It borders Cotabato province to the east, Maguindanao del Norte to the west, and Sultan Kudarat to the south.
According to Maguindanao royal records, Sharif Muhammad Kabungsuan of Johor introduced Islam to the Maguindanaos at the end of the 15th century. He subsequently married a Maranao princess of Malabang and established the Sultanate of Maguindanao.
The name of the island of Mindanao is from a 16th-century Spanish approximation of the name "Mangindanaw" which is at least a Tagalog exonym if not an endonym of the Maguindanao state and people.
Its capital of Kuta Watu (modern-day Cotabato) formed the sultanate's heartland but its influence extended from the Zamboanga Peninsula to Sarangani Bay and Davao.
In the 1660s, Dutch vessels from Ternate and Tidore often stopped by Maguindanao to purchase rice, beeswax and tobacco.
The Spanish frequently attacked the sultanate starting in the 1600s. In the middle of the 19th century, the Spanish were able to build a military post at what is now Barangay Tamontaka, Cotabato City.
The historical province of Cotabato covered the present area of Maguindanao. In 1903, the American colonial government established the Moro Province and made Cotabato as one of its districts. Upon the conversion of the Moro Province into the Department of Mindanao and Sulu in 1914, the districts were made into provinces.
In 1942, the Japanese forces first attacked what is now Maguindanao.
In 1945, Maguindanao was liberated by allied Philippine Commonwealth troops and Maguindanaon guerrilla units after defeating the Japanese Imperial forces in the Battle of Maguindanao during the Second World War.
The idea of creating a province in the present territory of Maguindanao del Norte dates back to 2006 when the province of Shariff Kabunsuan briefly existed for two years before being reverted as part of Maguindanao.
Maguindanao del Sur was formed when Maguindanao province was split into two provinces; the other province being Maguindanao del Norte. The division occurred following a plebiscite on September 17, 2022 which ratified Republic Act 11550 which proposed the partitioning of the province. As per law former Maguindanao Governor Mariam Mangudadatu was expected to become the governor of the newly formed Maguindanao del Sur province. However an issue arose since the determination of the first set of officials of the province presumes that the plebiscite was held prior to the 2022 national and local elections. However the plebiscite was postponed to a date after the elections. This led to the Commission on Elections to come up with a legal opinion. The position was issued on September 28, 2022, where the election body conclude that only the Department of the Interior and Local Government could appoint the first officials of the province.
Mangudadatu would assume the position and take oath as governor of the new province in October 13, 2022. Nathaniel Midtimbang, board member of Maguindanao's Provincial Board, became her vice governor. A transition period would take place until January 9, 2023.