I am rolling over a pension into my IRA. The check was dated in Dec. 2016, but the rollover won't be done until Jan. 2017. Should I claim this on my 2016 or 2017 taxes?

I had a similar situation myself a few years back:

1. You will get a 1099-R for 2016. Enter it in Wages and Income, Retirement.

2  In the follow up questions, indicate that you rolledd it over to an IRA within 60 days.

Be sure to keep copies of the dated pension check and all the rollover paperwork. You may hear from the IRS, due to the slip over from one tax year to the next,.

This was a lump sum pension distribution, right?

Yes. Thanks!

FYI: In my case, I did hear form the IRS, but not until a eyar later.

Thanks again. I always keep my tax records, & documentation, so should be OK if the IRS contacts me.

Did they take any withholding taxes out of it?  And did you put it in a Traditional IRA or a ROTH IRA account?

Lump sum distribution with no witholding. Going into my Traditional IRA.

A distribution and rollover of that distribution is reported in the tax year that the distribution was done, not the year of the rollover.  You should receive a  2016 1099-R after Jan 31 to enter in the Retirement, 1099-R section and indicate in the follow-up questions that it was a rollover.