Formula to return most recent instance of value?

Put this array* formula in B2 of Sheet2:

=MAX(IF('2011-2016_Orig'!$B$2:$B$16628=A2,'2011-2016_Orig'!$A$2:$A$16628))

Format the cell as a date, then copy down. Note the final 3 return zero as they are not present in your other sheet - this is interpreted by Excel as the zeroth of January 1900.

*An array formula needs to be committed using the key combination of Ctrl-Shift-Enter (CSE), instead of the usual < Enter >.

Hope this helps.

Pete

This works perfectly, thank you so so much!