In 2004 the U.S. Congress passed the Intelligence Reform and Terrorism Prevention Act, which established the Information Sharing Environment (ISE) to facilitate the exchange of terrorism-related information across the U.S. security apparatus. Since that time, the United States has greatly improved and expanded its information sharing infrastructure. Yet despite marked progress, the United States still faces significant information sharing challenges. As recent incidents have shown, rapid changes in information sharing practices, procedures and technology have had ramifications for both security and privacy. As the ISE and government information sharing efforts mature, technology, cultural, policy and legal mechanisms will have to continue to evolve and be strengthened to meet these challenges.