Sometimes applications are getting blocked by some countries and they can even be banned to use or some features of applications also can be blocked by countries. (Example: UAE has blocked video call, voice call features of most of messenger applications.) WhatsApp one of those applications which has been blocked or limited by some countries. If you will visit US and if you worry that WhatsApp is not working there, you should not worry about it. WhatsApp is allowed every states and cities of America at the moment and it won’t be hard for you to use this applications. There are already small amount of applications which has been blocked by United States of America governments with a reasonable reason.
WhatsApp also blocked in some countries in Europe, Asia, Africa, North America and South America.
North America: Belize
South America: Paraguay
Asia: China, Iran, Kuwait, Oman, Pakistan
There are limited blocks in some other Arab countries of Asia at the moment. These countries are United Arab Emirates and Saudi Arabia at the moment.
The only country who has blocked usage of WhatsApp in North America is Belize. You will able to use WhatsApp on United States, Canada and Mexico if you want to trip these countries.