SIRGAS is the Geocentric Reference System for the Americas. Its definition corresponds to the International Terrestrial Reference System (ITRS) and it is realized by a regional densification of the International Terrestrial Reference Frame (ITRF). Besides the geometrical reference system, SIRGAS includes the definition and realization of a vertical reference system, based on ellipsoidal heights as geometrical component and geopotential numbers (referred to a global conventional W₀ value) as physical component.

SIRGAS was created in 1993 during the International Conference for the Definition of a South American Geocentric Reference System held in Asuncion, Paraguay.  This conference was promoted and supported by the International Association of Geodesy (IAG), the Pan-American Institute for Geography and History (PAIGH), and the US National Imagery and Mapping Agency (NIMA), today National Geospatial-Intelligence Agency (NGA). The original acronym of SIRGAS (Geocentric Reference System for South America) was changed in 2001 to Geocentric Reference System for the Americas, since the SIRGAS2000 GPS campaign was extended to North- and Central America, and the United Nations Organization, through its 7^th Cartographic Conference for The Americas (New York, January 22 – 27, 2001), recommend to adopt SIRGAS as official reference system in all American countries.

SIRGAS is a member of the IAG Commission 1 (Reference Frames), through the Sub commission 1.3 (Regional Reference Frames), and it responsible for the Regional Reference Frame for South- and Central America (1.3b). SIRGAS is also a Working Group of the Cartographic Commission of the PAIGH.

The activities, resolutions, and challenges of SIRGAS are described in the different Newsletters generated during the SIRGAS Technical Meetings.

SIRGAS is the backbone for all projects based on the generation and use of geo referenced data in a national as well in an international level. Besides to provide the reference coordinates for the development of practical applications such as engineering projects, digital administration of geographical data, geospatial data infrastructures, etc., SIRGAS is also the platform for a wide range of scientific applications such as the monitoring of Earth's crust deformations, vertical movements, sea level variations, atmospheric studies, etc.