Start here: https://travel.state.gov/en/passports.html

Start here: https://travel.state.gov/en/passports/renew-replace.html

The Smart Traveler Enrollment Program (STEP) is a free service for U.S. citizens and nationals. It is optional. Benefits include updates about your destination and local U.S. embassy information. It also makes it easier for the Department of State to quickly and accurately contact you in case of emergency.

https://mytravel.state.gov/s/step

TSA’s “What Can I Bring” website is a very helpful tool.

https://www.tsa.gov/travel/security-screening/whatcanibring/all

The National Park Service has a very helpful app: https://www.nps.gov/subjects/digital/nps-apps.htm

Its benefits include interactive maps, offline use, news and alerts, etc.