Council of Graduate Schools

From their website:

For more than five decades, the Council of Graduate Schools (CGS) has been the national voice for the graduate dean community. CGS is the only national organization in the United States that is dedicated solely to the advancement of graduate education and research. 

CGS accomplishes its mission through advocacy in the policy arena, innovative research, and the development and dissemination of best practices. CGS also acts as a convening authority, organizing major events that bring together graduate deans and other stakeholders to discuss and take action on a broad range of issues affecting graduate education today.