April 15 landed on a weekend this year meaning that April 18, 2017 is the due date for U.S. citizens to file their 2016 U.S. tax return. However, if you are a U.S. citizen living outside the U.S., you are entitled to an automatic 2-month extension to file your return and pay any federal income tax that may be owing. This means that a U.S. citizen living in Canada has until June 15 to file their U.S. tax return.
If the automatic 2-month extension is not enough time, you may qualify for a 6-month extension by filing Form 4868 (which can be filed electronically) before the June 15 deadline. This would extend your U.S. tax filing deadline to October 16 (October 15 lands on a Sunday).
It is important to remember that even if you receive a 2 or 6-month extension, interest will accrue on any tax not paid by the regular due date of your return, i.e. April 18, 2017.