The Libunao Protected Landscape, also known as the Libunao Spring Protected Landscape, is a protected area in the Ilocos Region of the island of Luzon in the Philippines located on the western foothills of the Ilocos Mountain Range. It protects the Libunao Spring and surrounding forests, as well as the Nagcullooban River watershed. First proclaimed as the Libunao Spring Watershed Forest Reserve in 1931 through Proclamation No. 410 issued by Governor-General Dwight F. Davis, the park was reestablished as a protected landscape area under the National Integrated Protected Areas System in 2000 through Proclamation No. 280 signed by President Joseph Estrada. The Libunao watershed is the source of water supply for domestic use and irrigation of the surrounding farms and communities of northern Ilocos Sur province.