San Martin was declared a department in 1906. According to Garcilaso de la Vega , the province of Moyobamba was first penetrated and subdued by Tupac Yupanqui . In 1539 the Spaniard Alonso de Alvarado founded the town that was later to be the capital of Maynas (Moyobamba is in fact the oldest city in the Peruvian Amazon). Between 1787 and 1790 the Huallaga river was extensively explored by father Manuel de Sobreviela , who then published a map featuring a "Plan of the Course of the Rivers Huallaga and Ucayali and of the Sacramento Pampa". On August 26, 1821 Moyobamba solemnly endorsed Peru 's independence.

Gera falls - Moyobamba hot springs - Mayo river (fishing and canoeing).