BorderAround for Range (lastRow)

Sorry, misunderstood:

Const LastRow As Long = 10
Range(Cells(LastRow + 1, 1), Cells(LastRow + 1, 53)).BorderAround Weight:=xlThin

Dim lLR As Long
lLR = Cells(Rows.Count, 1).End(xlUp).Row
Range(Cells(lLR + 1, 1), Cells(lLR + 1, 53)).BorderAround Weight:=xlThin