The State Department's Foreign Relations of the United States (FRUS) series is the official historical record of major U.S. foreign policy decisions and significant diplomatic activity. The series began in 1861 and is available for dates up until about 40 years ago. For security purposes, there is a moving wall on release of information.
The official web site of the Department of Homeland Security. The site covers such topics as Border Security, Citizenship and Immigration Services, Civil Rights and Civil Liberties, Cybersecurity, Disasters, Economic Security, Human Trafficking, Immigration Enforcement, Preventing Terrorism, and Transportation Security.