CASA of Chemung County, Inc. began to form in 1988 when the New York Task Force on Permanency Planning and the Junior League of Elmira approached the Chemung County Family Court with information about the benefits to be gained through the use of CASA volunteers in Family Court. The first case was assigned in 1989.

In the summer of 1994, CASA received a Senate Initiative Grant from Senator Kuhl and a Schuyler County Youth Bureau grant to expand services to Schuyler County. CASA started providing services in Schuyler County in November of 1994. In 1996, a part-time Supervisor was hired to cover Chemung and Schuyler Counties. 

In August 2002, CASA expanded services into Steuben County and in January 2003 became CASA of the Southern Tier, Inc. 

Lastly, CASA began to serve the abused and neglected children of Yates County in November of 2021.   This expansion increased the service population to over 221,000 and the coverage area to 2500 square miles.