However this question is seeking to find the last row using VBA, I think it would be good to include an array formula for worksheet function as this gets visited frequently:
{=ADDRESS(MATCH(INDEX(D:D,MAX(IF(D:D<>"",ROW(D:D)-ROW(D1)+1)),1),D:D,0),COLUMN(D:D))}
You need to enter the formula without brackets and then hit Shift + Ctrl + Enter to make it an array formula.
This will give you address of last used cell in the column D.