As Hurricane Katrina so forcefully demonstrated, the nation's critical infrastructures and key resources have been vulnerable to a wide variety of threats. Because about 85 percent of the nation's critical infrastructure is owned by the private sector, it is vital that the public and private sectors work together to protect these assets. The Department of Homeland Security (DHS) is responsible for coordinating a national protection strategy including formation of government and private sector councils as a collaborating tool. The councils, among other things, are to identify their most critical assets, assess the risks they face, and identify protective measures, in sector-specific plans that comply with DHS's National Infrastructure Protection Plan (NIPP). GAO examined (1) the extent to which these councils have been established; (2) the key facilitating factors and challenges affecting the formation of the councils; and (3) the overall status of the plans and key facilitating factors and challenges encountered in developing them. GAO obtained information by reviewing key documents and conducting interviews with federal and private sector representatives. GAO is not making any recommendations at this time since prior recommendations are still being implemented. Continued monitoring will determine whether further recommendations are warranted.