Not 100% sure

I do not think that there is any meaningful time limit regarding how long a Canadian can stay in the US. At most the limit is symbolic, if any.
I remember that Canadian can do variety of work in the US without authorization as long as the pay is not from the US source. However, if they seek income from any US source, a work authorization is required for sure.

所有跟帖： 

• 我以前在旅行社工作时，同事有拿加拿大护照的，六个月必须出境一次 -xiaobaitu- ♀ (124 bytes) () 09/26/2006 postreply 17:00:15

• 这个180天基本上是无法ENFORCEABLE, 因此美国的官方网站 -mytwocents- ♂ (13 bytes) () 09/26/2006 postreply 20:45:58

• OK finally got the number somewhere. I know a few canadians -mytwocents- ♂ (23 bytes) () 09/26/2006 postreply 21:09:42