http://travel.state.gov/

Information regarding Visas for Foreign Citizens

https://esta.cbp.dhs.gov/

Electronic System for Travel Authorization to the US

http://wwwnc.cdc.gov/travel/

Traveler related health topics/ notices/ outbreaks/ and general news

http://www.tsa.gov/

US Transportation and Security  Administration Traveler, Airport Security, and Baggage information. TSA luggage lock information.

http://www.dhs.gov/index.shtm

http://www.dhs.gov/files/travelers.shtm

Department of Homeland Security – Immigration and order security

http://www.usa.gov/Citizen/Topics/Travel_Tourism/State_Tourism.shtml