Range.CurrentRegion is a rectangular range area surrounded by empty cells. Blank cells with formulas such as
' are not considered blank (even by the
ISBLANK Excel function).
Dim rng As Range, lastCell As Range
Set rng = Range("C3").CurrentRegion ' or Set rng = Sheet1.UsedRange.CurrentRegion
Set lastCell = rng(rng.Rows.Count, rng.Columns.Count)