Constraining the mobility of terrorists is one of the most effective weapons in the War on Terror. Limiting their movements markedly diminishes terrorists' ability to attack the United States, our interests abroad, or our allies. As both the 9/11 Commission noted in its main report and the 9/11 Commission staff noted in its separate monograph on terrorist travel, constraining the mobility of terrorists should be a key focus of the US Government's counterterrorism initiatives over the coming years. In light of the Commission's findings, Congress required the National Counterterrorism Center (NCTC) to submit this National Strategy To Combat Terrorist Travel (NSCTT) pursuant to Section 7201 of the Intelligence Reform and Terrorism Prevention Act of 2004 (IRTPA). The 9/11 terrorist attacks highlighted the need to improve the monitoring and control of the domestic and international travel systems as a means to constrain terrorist mobility. Since then, the US Government has made considerable progress toward achieving this objective. The post-9/11 security environment consists of strengthened travel document security, enhanced screening of all visitors to the United States, improved information-sharing relationships with foreign partners, and increased vigilance of the American people and our allies in the War on Terror. Our foreign partners have also made progress in strengthening border security and providing terrorist-related information to the United States in a timely and efficient manner. The terrorist enemies we face remain determined, patient, and adaptable. While new security measures are making terrorist travel more difficult, terrorists and illicit travel facilitators are continually seeking new ways to exploit perceived weaknesses in travel security: Terrorists seek to defeat travel and border systems by using illicit travel networks, including professional human smugglers. As legal entry into the United States becomes more difficult, terrorists increasingly may seek ways to exploit what they perceive as weaknesses in US and foreign border control operations. Further progress inhibiting terrorist mobility and suppressing the illicit travel industry will require sustained bilateral and multilateral international cooperation, including coordinated law enforcement, intelligence, and diplomatic initiatives. The goal of the NSCTT is to fight terrorist travel globally. The NSCTT identifies eight key steps necessary to achieve that goal. 1. Identify known or suspected terrorists. 2. Ensure broad data sharing across the US Government and with partner nations. 3. Screen travelers effectively both before reaching and at ports of entry into the United States. 4. Build partner capacity to limit and screen for terrorist travel. 5. Detect and apprehend terrorists who intend to enter, or who may have entered, the United States. 6. Dismantle infrastructures and networks that facilitate terrorist travel. 7. Strengthen travel and document security at home and abroad to ensure that terrorists cannot acquire documentation through legal or illicit means. 8. Collect, analyze and disseminate all terrorist travel information to key consumers across the counterterrorism and law enforcement communities.