This example selects the cell at the top of column B in the region that contains cell B4.
Range("B4").End(xlUp).Select
This example selects the cell at the end of row 4 in the region that contains cell B4.
Range("B4").End(xlToRight).Select
This example extends the selection from cell B4 to the last cell in row four that contains data.
Worksheets("Sheet1").Activate
Range("B4", Range("B4").End(xlToRight)).Select