As the result of an archeological excavation performed by Robert Fox at the Hacienda of Juan Escuetura in Bato, Sorsogon was assumed inhabited by prehistoric settlers. The project revealed relics of stone tools, burial jars and crowns. Some items indicated civilization from 91 B.C. to 79 A.D. Much of these evidences were also found in Bulan and Juban.
Sorsogon was discovered in 1569 by a group of Spanish missionaries named Father Alonzo Jimenez, Juan Orta and Captain Luis Entiquez de Guzman. They conducted their first mass in a small district of Bulan named Otavi and built the first chapel along the Ginangra River of Magallanes in 1571. The village, called Gibalong by its residents, became the first Christian settlement in Luzon. Later, the friars called the whole Bicol region "Tierra de Ibalong".
When the Spaniards had settled in Gibalong, they set out to further explore the inner lands. Upon reaching a small river emptying into what is now Sorsogon Bay, they asked a native they met for the name of the place. The native, not understanding Spanish and thinking they were asking for directions, answered, "Solsogon" meaning "trace the river by going upstream". Through constant use, Solsogon became Sorsogon.In the succeeding years they discovered more places and established their religious mission.
Due to its accessible location, Sorsogon was developed as a district for ship making and in 1669, the province became the center of cordage industry. For many years, Sorsogon underwent many Muslim raids. To keep them away, Captain Pedro constructed The Fort of Sirangan and built more towers in the coastal districts of Bacon, Bulusan, Sta Magdalena and Gubat.
Sorsogon became an independent region on October 17, 1894 with Juan de la Guardia as the first governor. During the outbreak of the Philippine Revolution, Father Jorge Barlin and Vicar Forane assumed administration of the province. He subsequently turned it over to the revolutionary forces.
During the American occupation in 1900, General William Kobbe ruled Sorsogon under a military government; causing more resistance to arise. After the capture of Emeterio Funes, head of the rebel forces, a civil government was established in Sorsogon under the leadership of Bernardino Monreal.
Japanese forces succeeded at invading Sorsogon in 1942. Salvador Escudero and Major Licerio organized its guerilla units with the assistance of Americans. Sorsogon was liberated on April 29, 1945.