Finding last cell in a column

[loloobaloo]

Hi friends I am going to write a Function in VBA that I should have first cell and last cell in a column. the first is easy but I don't know how I can do it for the last cell.
I don't know what should I write instead of x in the lastCell.
I hope you can help me

firstCell = Cells(1, 1)
lastCell = Cells(x, 1)

[georgiboy]

Something like:

Sub test()    
    Dim FirstCell As Range
    Dim LastCell As Range
    
    Set FirstCell = Cells(1, 1)
    Set LastCell = Cells(Rows.Count, 1).End(xlUp)
    
    Range(FirstCell, LastCell).Select
End Sub

[snb]

Sub M_snb()
  sn = sheet1.cells(1).currentregion
  msgbox sheet1.cells(ubound(sn),1)
End Sub