[5] During the Spanish colonization in the 16th century, a settlement surrounded a port in what is now Pasacao, serving as a primary embarkation point in Camarines Sur and the only sea link to Manila.Colloquially, "Pasacao" refers to this former settlement, which is still recognized separately as the modern town center housing government and business hubs.The settlement was designated as a town in 1854 and expanded to incorporate neighboring barrios, leading to the establishment of a municipality during the American colonial period in the early 20th century.While this isn't explicitly stated, it implies that these areas may have been regarded as distinct villages rather than part of a unified territory before any formal ratification.There was also uncertainty over whether the small boats that would utilize the canal would justify the expense,[12] and fears arose that seawater intrusion might threaten the town's rice fields.[10] In World War II, the Tangcong Vaca Guerilla Unit [bcl], based near Mount Bernacci, carried out significant operations against Japanese forces.[6] The Six Daughters of Charity arrived in Pasacao to establish Naga's first regular girls' school, Universidad de Santa Isabel.Various organizations, including the Philippine Red Cross and the Naga City Filipino-Chinese Chamber of Commerce, contributed food and supplies to support the affected residents.It shares its northwestern border with Libmanan, marked by Mount Bernacci, while San Fernando lies to the east and Pamplona to the north.The western area mainly features rolling hills that are part of the highlands surrounding the Ragay Gulf, with the terrain primarily consisting of limestones,[15] sandstones, and marls.Despite the presence of a single church, Saint Rose of Lima Parish, and a few chapels, Roman Catholicism is the dominant religion in the municipality.The Public Market serves as the main commercial center of Pasacao, bustling with economic activity from the trading of agri-fishery products and dry goods.[15] As of 2015, Pasacao had 19 industrial establishments, categorized into Construction, Electricity, Gas and Water, Mining and Quarrying, and unclassified sectors.[15] While the tourism industry generates jobs and fosters skill development, Pasacao remains relatively underdeveloped as a tourist destination despite its rich cultural history and natural resources.[15] The municipality has no sanitary landfill but maintains three (3) Materials Recovery Facilities, which are located in Caranan, San Cirilo and Santa Rosa del Sur.[36] Together, these road networks play a crucial role in supporting transportation and economic development in Pasacao and its surrounding regions.