GRASS has been under continuous development since 1982[3] and has involved a large number of federal US agencies, universities, and private companies. The core components of GRASS and the management of integration of efforts into its releases was originally directed by the U.S. Army - Construction Engineering Research Laboratory (USA-CERL), a branch of the U.S. Army Corps of Engineers, in Champaign, Illinois. USA-CERL completed its last release of GRASS as version 4.1 in 1992, and provided five updates and patches to this release through 1995.