Barangay Udiao

Classified as a mid-sized barangay, Barangay Udiao is one of the administrative divisions of Rosario in La Union, Ilocos Region, Philippines.

According to the 2020 Philippine census, Barangay Udiao had a population of 2,553. This made it the 8th largest of 33 barangays in Rosario by population, placing it in the upper half of the municipality. Residents of Barangay Udiao accounted for approximately 4.24% of the total population of Rosario, which stood at 60,278 in the same census year.

Between the 2015 and 2020 censuses, the population of Barangay Udiao changed from 2,592 to 2,553, a shift of -1.5% over the five-year period. This places the barangay among those with broadly stable populations in Rosario. Barangay Udiao is officially classified as urban, reflecting the density and built-up character of the area.

Rosario is a municipality comprising 33 barangays, and serves as the governing unit directly responsible for local services in Barangay Udiao, including public health, sanitation, peace and order, and civil registration. Within the wider province of La Union, which contains 576 barangays across its component cities and municipalities, Barangay Udiao ranks 59th by 2020 population. La Union is classified as a 1st by the Bureau of Local Government Finance, a category that reflects the province's annual regular income.

The barangay's legislative and executive affairs are handled by a Punong Barangay and the Sangguniang Barangay, elected nationwide during the Barangay and SK Elections. The next BSKE is scheduled for Monday, November 2, 2026, following the synchronized election schedule set by COMELEC Resolution No. 11191.