Mindanao is the second largest and easternmost island in the Philippines and one of the three island groups in the country, with Luzon and Visayas being the other two. The region first came to contact with Spain in the late 16th to early 17th century by Spanish soldiers and friars who colonized it in 1622.

These days the region is home to the country's Muslim or Moro populations, comprising of many ethnic groups such as the Maranaos and the Tausugs, and the collective group of tribes known as the Lumad. Contrary to the common belief, not all parts of Mindanao have been conquered by the Muslims. In fact, most of Northern Mindanao, Eastern Mindanao, Western Mindanao and Southern Mindanao people were animistic before they were converted to Christianity.

A bitter independence struggle has been waged by various Muslim factions for five centuries against successive occupiers. Spanish, U.S., Japanese and Filipino government forces failed to quell their desire to separate from the largely Christian nation. Due to influx of immigrants to the region, the majority of Mindanao's population is now predominantly Christian, a regional issue that fuels the anger of poor and displaced Mindanaoan Muslims and the separatist movements that have been fighting for hundreds of years.

In recent years, the area has come under scrutiny, with the rise of Islamic terrorist organizations tied to the Middle East conflict. Mindanao is a staging ground for such terrorist groups as Abu Sayyaf and Jemaah Islamiyah that undermine the more moderate and nationalistic aspirations of independence seekers like the Moro Islamic Liberation Front (MILF).

As an island in the southern part of the country, Mindanao is the second largest at 94,630 square kilometers, only about 10,000 km² smaller than Luzon. The island is mountainous, and is home to Mount Apo, the highest mountain in the country. To the west of Mindanao island is the Sulu Sea, to the east is the Philippine Sea, and to the south is the Celebes Sea.

The island group of Mindanao encompasses Mindanao island itself, plus the Sulu Archipelago to the southwest. The island group is divided into six regions, which are further subdivided into 25 provinces.