Made an extension payment for my 2016 federal taxes, do I enter that somewhere when doing my 2017 taxes?

[AnnetteB]

No, a payment for your 2016 Federal taxes made in 2017 would not be reported on your 2017 return.

That payment would be accounted for on your 2016 Federal return which you completed and later in the year. 

If you made any payments for state or local taxes for 2016 by filing an extension in 2017, then those payments would be entered on your 2017 Federal return.  They would become a deduction on Schedule A.  (Use the search term “tax payments” to find the section of the return to enter that type of payment.)