No, but under the United States' Western Hemisphere Travel Initiative (WHTI), the other documents you could use instead of a passport are fairly limited:
U.S. citizens can present a valid: U.S. Passport; Passport Card; Enhanced Driver’s License; Trusted Traveler Program card (NEXUS, SENTRI or FAST); U.S. Military identification card when traveling on ...
You need either a passport, a Nexus card or an Enhanced Driver's License to enter Canada. See this.
For returning, you can use a passport, Nexus card, Enhanced Driver's license or a birth certificate. Official information here.
So, to answer your title question, no, but you do need another proof of citizenship.
Usually they dont check anything except your passport and visa.
but better to carry
1.Invitation letter (Incase of a business visa)
2.Travel Insurance (Mandatory document, should cover the travel duration)
3.Accomodation proof (Hotel bookings)
4.Air Tickets (to and fro)
In general, yes you will need some form of identification, even if you are British or Irish (counterintuitively, as evidence of this fact, so that you then don't legally need identification), but it doesn't necessarily need to be photo ID such as a passport.
The precise rules will depend on your carrier, but to quote from the Stena Line FAQ:
I’M A ...
I want to contribute for the above answer for some:
Actually, there are many websites that offer Vietnam visa services like https://www.vietnam-visa.com/, https://vietnamvisa.govt.vn, https://www.vietnam-evisa.org/, and many more.
They are all approved by the Vietnam government to process visa service. However, it's worth noting that the one with "govt.vn" ...