Planned a move in new primary in April 2017 and provided that as my address on 2016 returns. However move got delayed until Oct 18. Which is my primary during that time?

[RachelW33]

Up until Oct 2018, your primary residence will be the home you lived in prior to the move.  Using the address on your 2016 Tax return does not affect anything as long as you filed a state tax return for the state you actually resided in (if required).

If you moved to a different state, you will need to file part-year state tax returns based on the time you lived in each state during the tax year.  Under the "My Info" section, TurboTax walks you through a series of interview questions to determine what state returns you need to file.

[TomD8]

The address you put on your tax return should be the address you want the IRS to use in case they need to contact you by mail.   It's also the address the IRS will use to mail your refund check, if you don't choose to have your refund direct-deposited to your bank.  It's simply your mailing address, nothing more.