US Department of State 

Travel information home page: http://travel.state.gov

STEP - Smart Traveler Enrollment Program: https://step.state.gov/step

Passports: https://travel.state.gov/content/passports/en/passports.html

Country Information: http://travel.state.gov/content/passports/english/country.html

Traveler's Checklist: http://travel.state.gov/content/passports/english/go/checklist.html

US Embassy and Consulate Finder: https://www.usembassy.gov/

Customs and Border Protection

US Customs information: https://www.cbp.gov/travel/us-citizens/know-before-you-go

 Trusted Traveler Programs - TSA Precheck, Global Entry, Nexus, Sentri: https://www.cbp.gov/travel/trusted-traveler-programs