Pilar is one of the 14 municipalities of the province of Sorsogon, created on August 6, 1861 as a  cluster of the visitas of Sto. Niño, Panlatuan, Ynang, Putiao, San Antonio, and Cadanlogan that together met the minimum requirement of at least 500 tribute-payers. It is located at the northwestern part of the province and bounded on the north by the province of Albay, in the south by Pilar Bay, in the east by the municipality of Castilla and in the west by the municipality of Donsol.

The municipality is composed of 49 Barangays grouped into two districts. Its land area is 24,815.20 hectares or 248.15 sq. kilometers which makes it the largest municipality in the province in terms of land area.

Like the rest of the municipalities in the Bicol Region, Pilar experiences fairly continuous rainfall throughout the year and is visited by an average of 15 tropical cyclones every year.

Pilar’s economy is predominantly agricultural. Despite efforts on diversification, it is still heavily  dependent on the monoculture of coconut which is planted to about 70% of its total land area. As such, it is a major supplier of copra in the coconut milling industry in Bicol. Other common agricultural products include rice, corn, banana and root crops. Next to agricultural farming, fishing is the most common economic activity and the main source of income of many coastal residents. Pilar, after all, is considered as one of the richest fishing grounds in the vicinity. Including its more than 300 hectares of fish pond, Pilar is one of the major supplier of fishery products in Metro Manila.

It is also considered as the preferred transshipment point of Bicol Region to the island province of Masbate and other Visayan Islands being in the ideal route of the Central Nautical Highway of the Roll-On, Roll-Off national maritime connectivity.

Eco-tourism is one of the potentials of the municipality.  Presently, the LGU Pilar Tourism office promotes the following attractions:  Caves located at the barangays of San Jose and Lungib, Marine Reserve and Sanctuary, Panlatuan Cove, Panumbagan Sand Bar, Egret Sanctuary at Sacnangan, foreshore white sands  San Antonio (Sapa), Inapugan and Bantayan and the richly endowed mangrooves along the Putiao and Malbog rivers.

As of 2010 census, its total population is 68,245 registering a growth rate of 1.66 from 57,898 census count in 2000. It has a very large labor force and the basic paying requirement is relatively low.

Presently, the municipality of Pilar is classified as 1^st class with a revenue adding up to P118,109,679.00.