Passport needed to travel to USA?

Do Canadians (with a Canadian birth certificate) need to have a passport to travel to the USA or specifically New York?

What about Canadian citizens born outside Canada but now have citizenship with Canada?

U.S. Bureau of Immigration and Citizenship Services:

(Emphasis mine.) Source: http://www.voyage.gc.ca/main/pubs/usa_bound-en.asp

FWIW, the US Embassy web site for Canada sucks. I could not find any helpful information.

I crossed twice recently and only showed my Driver’s Licence. Of course, I’m white and have no accent when I speak, and I’m a born Canadian.

As others have already posted, you don’t have to have a passport, but its a damned good idea. Second best is proof of citizenship (birth certificate or citizenship certificate) plus a government issued photo ID (driver’s license). Anything less and you might be in for a nasty surprise.

If you cross in a car, ID checking is often fairly lax, but if you are the “lucky winner”, it will be more thorough. If you cross on a bus/train/plane, checking is a little more strict.

I’m Canadian born, white, english, no accent, clean record. Lived in Canada for my first 25 years, then moved the US. I have crossed the border at least 100 times, and I have been pulled aside 3 times. If I only had a driver’s license, it would have made a bad situation worse. The times I was pulled aside were all before 9/11 - I have good reason to believe that border security would be even less humourless now.

If you don’t look “Canadian” (i.e. non-white or non-native english or french speaker), your chances of an extended meeting with customs appears to be much higher.

FWIW neither United or Air Canada will board you in the states bound for Canada unless you have a passport in hand.
This goes along with what Duckster posted