Posted: Mon May 05, 2008 9:32 pm-
Yes, January 1st. Assuming your tax home is now the US. If it's not and you carried on paying Canadian income tax, it doesn't really matter and you just have to declare to the IRS that you left the country, although you will have to file a US tax return (1040NR and whichever tax treaty form is relevant to you, probably an 8833) for the portion of the year you were in the US.
This is not really linked to where you physically are, it's where you decide your principal residence is. You can decide your principal residence is Canada at some point other than when you physically arrive, either before or after.
It depends on where you have "residential ties".
http://www.cra-arc.gc.ca/E/pub/tg/p151/README.html_________________
Steve.