Diadi

Diadi, officially the Municipality of Diadi, is a municipality in the province of Nueva Vizcaya in the Cagayan Valley region of the Philippines. The municipality uses Diadi in English and Filipino contexts, while local forms include Ili na Diadi in Gaddang, Ili ti Diadi in Ilocano, and Bayan ng Diadi in Tagalog. It is part of Nueva Vizcaya's lone congressional district and is administered through the Philippines' local-government system, with an elected mayor, vice mayor, and municipal council. According to the 2024 census, Diadi had a population of 20,438 people. The settlement has roots in the Spanish colonial period. It was originally known as Picat and was formerly a barangay of Bagabag. Spanish authorities established the settlement in the eighteenth century on the summit of Mount Namamparang before relocating it to the mountain's foot. Its early role was shaped by geography and security: it served as a garrison and resting point on the mountain route linking Isabela and Nueva Vizcaya, an area historically affected by attacks from groups described in colonial sources as pagan headhunters. The settlement also became a site for the resettlement of Christianized Ifugaos and Ilongots. Diadi became a separate municipal unit through Republic Act No. 4973. The legislation began as House Bill No. 182, introduced by Congressman Leonardo B. Perez on February 28, 1966. After review by the relevant congressional committee and a favorable Senate committee report, the measure was approved by both chambers and became law on June 17, 1967. This formalized Diadi's municipal status and established the administrative foundation for its subsequent development. The municipality lies about 40.11 kilometers from Bayombong, the provincial capital, and approximately 337.52 kilometers from Manila. It is politically divided into 19 barangays, which are further organized into puroks and, in some cases, sitios. Its landscape is associated with the Magat River and surrounding upland and agricultural areas. The Lower Magat Eco-Tourism Park is a notable local attraction. The 1,200-hectare site was acquired by the provincial government for preservation and later developed as a nature park with lagoons, camping areas, swimming pools, cottages, and facilities for outdoor activities including hiking and bicycling. Diadi's economy is primarily rural. Agriculture and fisheries are important local activities, and the municipality has been connected to the expansion of tilapia aquaculture in Cagayan Valley. In the late 2000s, government fisheries programs supported the regional industry by distributing improved fish stocks and fingerlings, accrediting private hatcheries, establishing demonstration farms, and assisting newly developed fishponds. Diadi was identified as one of the Nueva Vizcaya locations where tilapia production was disseminated. These activities formed part of a broader regional development effort rather than a single commercial brand operation. Public education in Diadi is administered through the Nueva Vizcaya Schools Division and the Diadi Schools District Office, which oversee public and private elementary and secondary education. Schools identified in reference material include Diadi National High School and St. Joseph School. As a municipality rather than a consumer-facing company, Diadi's principal public-facing functions are local administration, public services, education coordination, infrastructure, environmental management, and support for agriculture, fisheries, and tourism.

Diadi developed from a settlement historically known as Picat, which was formerly a barangay of Bagabag. Spanish authorities established the settlement during the eighteenth century on Mount Namamparang and later moved it to the foot of the mountain. Its location along the route between Isabela and Nueva Vizcaya gave it strategic importance. The settlement operated as a garrison and rest stop on a road that colonial accounts described as vulnerable to attacks by groups labeled as pagan headhunters. It also served as a resettlement location for Ifugaos and Ilongots who had been Christianized. For much of its earlier administrative history, Diadi remained under Bagabag. Its transition to an independent municipality was pursued through national legislation in the 1960s. Congressman Leonardo B. Perez introduced House Bill No. 182 on February 28, 1966, proposing the creation of a municipal district of Diadi in Nueva Vizcaya. The proposal received a favorable report from the Committee on Provincial and Municipal Governments. In the Senate, Committee Report 1053 recommended passage in May 1967. Republic Act No. 4973 was subsequently approved by both chambers of Congress and signed into law on June 17, 1967, creating the Municipality of Diadi. Modern Diadi is a local-government unit in Nueva Vizcaya's lone congressional district. It is governed under the Philippine Local Government Code by an elected mayor as local chief executive, a vice mayor, and a municipal council. Elections for these offices are held every three years. The municipality is divided into 19 barangays, each containing puroks and, in some cases, sitios. The municipality's physical setting is linked to the Magat River and the uplands of Nueva Vizcaya. A major tourism and conservation feature is the Lower Magat Eco-Tourism Park, a 1,200-hectare area acquired by the provincial government for preservation and later developed as a nature park. Its facilities include lagoons, camping grounds, swimming pools, cottages, and spaces for hiking and bicycling. The park gives Diadi a recreational and environmental role within the province in addition to its administrative function. Economic activity is largely rural, with agriculture and fisheries forming important parts of the local economy. Diadi was included in efforts to expand tilapia culture in Nueva Vizcaya during the 2000s. Regional programs promoted faster-growing fish varieties, quality fingerling supply through accredited hatcheries, demonstration farms, and the distribution of fingerlings to new fishponds. The municipality's fisheries activity was part of the wider Cagayan Valley aquaculture economy rather than evidence of a separately incorporated commercial brand. Education is administered through the Nueva Vizcaya Schools Division, a Department of Education field structure serving the Cagayan Valley region, while the Diadi Schools District Office coordinates public and private elementary and secondary schools in the municipality. Diadi National High School and St. Joseph School are identified among its secondary-level institutions. The 2024 census recorded 20,438 residents, reflecting the municipality's continuing role as a small rural community in Nueva Vizcaya.

• 2024

  Population recorded at 20,438

  [1]Diadien.wikipedia.org

  The 2024 Philippine census recorded 20,438 residents in Diadi.

• 2008

  Tilapia aquaculture expansion reported

  [1]Diadien.wikipedia.org

  Regional fisheries authorities reported the continued expansion of tilapia production and identified Diadi as one of the Nueva Vizcaya locations receiving support for aquaculture development.

• 1967

  Diadi becomes a municipality

  [1]Diadien.wikipedia.org

  Republic Act No. 4973 was approved on June 17, 1967, formally creating the Municipality of Diadi.

• 1966

  Municipal creation bill introduced

  [1]Diadien.wikipedia.org

  Congressman Leonardo B. Perez introduced House Bill No. 182 to create a municipal district of Diadi in Nueva Vizcaya.

• 1700

  Spanish-era settlement established

  [1]Diadien.wikipedia.org

  The settlement later associated with Diadi was established by Spanish authorities in the eighteenth century on Mount Namamparang before being moved to the mountain's foot.

A rural municipality in Nueva Vizcaya combining local government services with agricultural, fisheries, environmental-preservation, and nature-tourism activities.

1. 1Diadien.wikipedia.org
2. 2Official website of the Municipality of Diadidiadi-nvizcaya.gov.ph