Wat Ounalom was built by King Punyear Yat in 1442. King Punyear Yat built not only Wat Ounalom but also five other pagodas that can still be found in Phnom Phenh: Wat Koh, Wat Langka, Wat Preah Put Ku Sa, Wat Peom Tlong, and Wat Ta Yong. These five Wats are the oldest Wats in Phnom Penh. Facing the Tonle Sap River, Wat Ounalom is 149 meters long and 169 meter wide and has 40 buildings. In 2011, there were 375 monks and 700 students living in the pagoda, as poor boys from provinces who cannot afford a dorm room stay in pagodas in order to continue their studies in Phnom Penh, the so-called Pagoda Boys.