Dilasag [ˌdilɐˈsag], officially the Municipality of Dilasag (Tagalog/Kasiguranin: Bayan ng Dilasag; Ilocano: Ili ti Dilasag), is a municipality in the province of Aurora, Philippines. According to the 2020 census, it has a population of 17,102 people.

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The name "Dilasag" is divided into two syllables. The prefix Di in the native language means "abundance", added to the word lasag which means "meat". The coined word "Dilasag", however, does not only mean abundance of meat in the place, but also refers to the over sufficient supply of forest products, marine products and minerals.

In early 1924, a group of Ilocano settlers with a number of Kapampangans and Pangasinenses from Tarlac arrived in Casiguran, which was then part of Nueva Vizcaya. Finding the natives unfriendly to them, the settlers moved along the coastline going north and settled finally to what is now called Dilasag. The place was considered habitable, because the native Dumagats in the place were friendly. Later, more families came, establishing a community. This community was soon recognized by the mayor of Casiguran, by then a municipality of Quezon. It was declared a sitio of barangay Culat and eventually a barrio of Casiguran in consideration of its rapid progress and development. In 1959, Quezon 1st District Representative Manuel Enverga introduced House Bill No. 2863 in the House of Representatives, resulting in the approval of Republic Act No. 2452 on June 21, 1959, making Dilasag a municipal district and separating it from Casiguran. It was then part of the province of Quezon under the sub-province of Aurora until the latter became a province of its own in 1979.

According to the Philippine Statistics Authority, the municipality has a land area of 306.25 square kilometres (118.24 sq mi)  constituting 9.73% of the 3,147.32-square-kilometre- (1,215.19 sq mi) total area of Aurora.

Dilasag is 142 kilometres (88 mi) from the provincial capital Baler and 373 kilometres (232 mi) from Manila.

Dilasag is politically subdivided into 11 barangays. Each barangay consists of puroks and some have sitios.

PSGC	Barangay	Population			±% p.a.
		2020		2010
037703001	Diagyan	14.1%	2,418	2,537	▾	−0.48%
037703002	Dicabasan	4.3%	734	677	▴	0.81%
037703003	Dilaguidi	5.4%	915	1,015	▾	−1.03%
037703004	Dimaseset	8.3%	1,420	1,408	▴	0.08%
037703005	Diniog	14.5%	2,485	2,331	▴	0.64%
037703011	Esperanza	7.4%	1,266	1,241	▴	0.20%
037703006	Lawang	3.0%	511	379	▴	3.03%
037703007	Maligaya (Poblacion)	10.9%	1,869	1,801	▴	0.37%
037703008	Manggitahan	10.2%	1,742	1,760	▾	−0.10%
037703009	Masagana (Poblacion)	10.8%	1,841	1,822	▴	0.10%
037703010	Ura	3.7%	634	712	▾	−1.15%
	Total		17,102	15,683	▴	0.87%

Population census of Dilasag

Year	Pop.	±% p.a.
1960	2,481	—
1970	5,995	+9.21%
1975	3,566	−9.89%
1980	6,716	+13.49%
1990	11,195	+5.24%
1995	12,825	+2.58%
2000	14,676	+2.93%
2007	14,833	+0.15%
2010	15,683	+2.05%
2015	15,835	+0.18%
2020	17,102	+1.52%
Source: Philippine Statistics Authority

In the 2020 census, Dilasag had a population of 17,102. The population density was 56 inhabitants per square kilometre (150/sq mi).

Poverty incidence of Dilasag

10 20 30 40 2006 34.80 2009 19.15 2012 13.94 2015 12.39 2018 12.87 2021 21.41 Source: Philippine Statistics Authority

Coastal areas of Dilasag feature white sand beaches and fresh sea foods. With its mountainous terrain, Dilasag also provides an ideal venue for trekking and mountain-climbing.

• Canawer Beach
• Parang Hills
• Diniog Beach
• Mangrove Forest Park
• Singep Falls

The municipality is also home to the Amro River Protected Landscape.

• Philippine Standard Geographic Code
• Dilasag on Aurora.ph