Davao City is the largest city in the Philippines by land area. The region's name is derived from its Bagobo origins. The word davao came from the phonetic blending of three Bagobo subgroups' names for the Davao River, a major waterway emptying into the Davao Gulf near the city. The aboriginal Obos, who inhabit the hinterlands of the region, called the river Davah. -WikiPedia