Datu Piang (third from right) controlled much of the sa laya realm during the American colonial era.
The Maguindanaon people—the largest ethnolinguistic group in Central Mindanao—occupy the basin of the Pulangi River (Rio Grande de Mindanao in Spanish accounts), which spills down the southern slopes of the Bukidnon massif in north-central Mindanao, snaking south and west across a low-lying marshy plain to Illana Bay[i]. About twenty miles before reaching the sea the Pulangi splits into two branches. The narrower southern fork is known as the Tamontaka River. Near the mouth of the river, stands Timako Hill, and offshore, the dark crescent of Bongo Island. The wider north fork of the Pulangi flows past Cotabato City, which is located on its south bank about four miles above the river mouth[ii].
In the past, the Maguindanaon settled along riverbanks and in the valley regions of the Pulangi River where periodic flooding was experienced. It is due to this inundation that the people occupying the area came to be called maguindanaon –“people of the flood plains.” Today, they are found in several provinces. Maguindanao province accounts for 76 percent of the total Maguindanaon population. In Cotabato province, they are concentrated mainly in Pikit, Kabacan, and the interior villages of Midsayap. In Sultan Kudarat province, they live in Lutayan, as well as the coastal towns of Lebak, Kalamansig, and Palembang. They are also found in Malapatan, in Sarangani province, and Dinas and Labangan in Zamboanga Sibugay.