Onzaga is a town and municipality located in the Santander Department of northeastern Colombia. It is situated approximately 177 kilometres (110 mi) south of Bucaramanga, which serves as the department's capital.
The municipality shares borders with several neighboring areas: San Joaquín to the north; Coromoro to the west; and Soatá, Covarachía, Tipacoque, and Tutazá in the Boyacá Department to the east and south. The region is characterized by diverse topography, with elevations ranging from 900 metres (3,000 ft) to 3,600 metres (11,800 ft).