Returns the maximum legal column number (counting from 0)
static long MaxRow( );
The maximum legal row number, counting from 0 for the top-most row.
This is 16383 in all versions of Excel before 8 (Excel 97). For Excel 8 to 11 it is 65535. For Excel 12 it is 1048575.
You can find more information about the limits of array sizes in System Limits.